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Sökning: WFRF:(Yang Xichuan)

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1.
  • An, Jincheng, et al. (författare)
  • Fine-Tuning by Triple Bond of Carbazole Derivative Dyes to Obtain High Efficiency for Dye-Sensitized Solar Cells with Copper Electrolyte
  • 2020
  • Ingår i: ACS Applied Materials and Interfaces. - : NLM (Medline). - 1944-8244 .- 1944-8252. ; 12:41, s. 46397-46405
  • Tidskriftsartikel (refereegranskat)abstract
    • Three novel dyes consisting of a 5,8,15-tris(2-ethylhexyl)-8,15-dihydro-5H-benzo[1,2-b:3,4-b':6,5-b″]tricarbazole (BTC) electron-donating group and a 4,7-bis(4-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazole (BTBT) π-bridge with an anchoring group of phenyl carboxyl acid were synthesized and applied in dye-sensitized solar cells (DSCs).The AJ202 did not contain any triple bonds, the AJ201's ethynyl group was inserted between the BTC and BTBT units, and the AJ206's ethynyl group was introduced between the BTBT moiety and the anchor group. The inclusion and position of the ethynyl linkage in the sensitizer molecules significantly altered the electrochemical properties of these dyes, which can fine-tune the energy levels of the dyes. The best performing devices contained AJ206 as a sensitizer and a Cu(I/II) redox couple, which resulted in a power conversion efficiency (PCE) up to 10.8% under the standard AM 1.5 G illumination, which obtained PCEs higher than those from the devices that contained AJ201 (9.2%) and AJ202 (9.7%) under the same conditions. The highest occupied molecular orbital and lowest unoccupied molecular orbital levels of the sensitizers were tuned to be well-suited for the Cu(I/II) redox potential and the Fermi level of TiO2. The innovative synthesis of a tricarbazole-based donor moiety in a sensitizer used in combination with a Cu(I/II) redox couple has resulted in relatively high PCEs.
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2.
  • Deng, Zijian, et al. (författare)
  • Helical Copper Redox Mediator with Low Electron Recombination for Dye-Sensitized Solar Cells
  • 2021
  • Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:15, s. 5252-5259
  • Tidskriftsartikel (refereegranskat)abstract
    • Redox mediators play a major role in determining the photocurrent and photovoltage in dye-sensitized solar cells (DSSCs). Copper complexes are a good option for redox mediators but suffer from electron recombination. The traditional method is to add 4-(tert-butyl)pyridine (TBP) to the electrolyte, which is coordinated with the empty orbit of Ti, thereby slowing down the oxidized mediator's ability to capture electrons. However, this strategy will result in competitive coordination between the redox mediator and TBP, decreasing the stability of the device. In this study, two helical copper(I) complexes are synthesized and applied to TBP-free solar cells. La (1,3-bis(2,2'-bipyridin-6-yloxy)propane) and Lb (1,3-bis[(6'-methyl-2,2'-bipyridin-6-yl)oxy]propane) tend to form double-stranded helicates ([Cu-2(Ln)(2)](2+), n = a, b) rather than mononuclear complexes ([Cu(Ln)](+), n = a, b). To facilitate quantitative analysis of the complexes, Cu(I)Ln and Cu(II)Ln (n = a, b) are used as molecular formulae. (CuLa)-La-I and Cu(I)Lb are characterized by electrospray mass spectroscopy, H-1 NMR spectroscopy, and electrochemistry. J-V measurement shows that both V-oc and J(sc) increase with the increase of (CuLa)-La-I concentration (below 0.1 M), and the best power conversion efficiency is 8.2%. The relationship between Cu(I) concentration and recombination for further study was measured by IMVS.
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3.
  • Teng, Chao, et al. (författare)
  • Influence of Triple Bonds as pi-Spacer Units in Metal-Free Organic Dyes for Dye-Sensitized Solar Cells
  • 2010
  • Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:25, s. 11305-11313
  • Tidskriftsartikel (refereegranskat)abstract
    • Four metal-free organic sensitizers (TC101-TC104) with triple bonds in pi-spacers and five reference dyes (TC, TC105, TPC1, D5, and TH208) without triple bonds were applied in dye-sensitized solar cells to study the influence of triple bonds as pi-spacer units on their photoelectrochemical properties and dye-sensitized solar cells (DSCs) performance. Results show that the introduction of triple bond could red-shift the dye's absorption spectrum due to the enhancement of the pi-spacer. However, the spectrum red-shift is much less than that of the introduction of double bond because of more electronegativity of triple bond. The incident photon-to-current conversion efficiency reveals that the electron transfer yield (Phi(nu)(ET)) of DSCs becomes larger with the introduction of triple bond. Electrochemical impedance spectroscopy analysis reveals that the introduction of triple bond almost does not change the electron lifetimes in TiO2 films but decreases the effective diffusion lengths.
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4.
  • Teng, Chao, et al. (författare)
  • Molecular Design of Anthracene-Bridged Metal-Free Organic Dyes for Efficient Dye-Sensitized Solar Cells
  • 2010
  • Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:19, s. 9101-9110
  • Tidskriftsartikel (refereegranskat)abstract
    • A series of metal-free organic dyes bridged by anthracene-containing pi-conjugations were designed and synthesized as new chromophores for the application of dye-sensitized solar cells (DSCs). Detailed investigations on the relationship between the dye structures, photophysical properties, electrochemical properties, and performances of DSCs are described. With the introduction of the anthracene moiety, together with a triple bond for the fine-tuning of molecular planar configurations and to broaden absorption spectra, the short-circuit photocurrent densities (J(sc)) and open-circuit photovoltages (V-oc) of DSCs were improved to a large extent. The improvement of J(sc) is attributed to much broader absorption spectra of the dyes with the anthracene moiety. Electrochemical impedance spectroscopy (EIS) analysis reveals that the introduction of the anthracene moiety suppresses the charge recombination arising from electrons in TiO2 films with I-3(-) ions in the electrolyte, thus improving V-oc considerably. On the basis of optimized molecular structures and DSC test conditions, the dye TC501 shows a prominent solar energy conversion efficiency (eta) up to 7.03% (J(sc) = 12.96 mA . cm(-2), V-OC = 720 mV, ff = 0.753) under simulated AM 1.5 irradiation (100 mW . cm(-2)).
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5.
  • An, Jincheng, et al. (författare)
  • Thiophene-fused carbazole derivative dyes for high-performance dye-sensitized solar cells
  • 2021
  • Ingår i: Tetrahedron. - : Elsevier BV. - 0040-4020 .- 1464-5416. ; 88
  • Tidskriftsartikel (refereegranskat)abstract
    • Two novel dyes that are similar in chemical structure, except for different donor units, AJ301and AJ303 were synthesized, characterized and applied as sensitizers in dye-sensitized solar cells (DSSCs). Both dyes exhibited a wide absorption of visible sunlight. The introduction of fused rings on the donor unit of AJ303 presented an appropriate energy level, less recombination and longer electron lifetime to achieve a power conversion efficiency (PCE) of 10.2%, far above that achieved for AJ301 of 6.2% with a [Co(bpy)(3)](2+/3+)-based electrolyte under standard AM1.5G solar irradiation (100 mW cm(-2)). The DSSCs based on AJ303 and AJ301 with [Cu(tmby)(2)](2+/+)-based electrolyte showed a lower PCE of 8.2% and 5.4%, respectively. Therefore, the results indicated that the introduction of a fused-ring in the donor group is a meaningful synthetic strategy to improve the photovoltaic performance.
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6.
  • Cai, Bin, et al. (författare)
  • Boosting the power conversion efficiency of perovskite solar cells to 17.7% with an indolo[3,2-b]carbazole dopant-free hole transporting material by improving its spatial configuration
  • 2019
  • Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 7:24, s. 14835-14841
  • Tidskriftsartikel (refereegranskat)abstract
    • The development of facilely synthesized, dopant-free hole-transporting materials (HTMs) with high efficiency is of great significance for the potential application of perovskite solar cells (PSCs). Herein, we report two novel indolo[3,2-b]carbazole (ICZ) based small molecules obtained via a three-step reaction in a high yield without using expensive catalysts, namely C201 and C202, and further apply them as dopant-free HTMs in PSCs. Compared with C201, C202 contains two additional biphenylamino groups to improve its spatial configuration. It is found that the interplay between the molecular geometry and the aggregation behavior can exert a great influence on the film formation property and thus on the device performance. Strikingly, the champion devices employing C202 as the HTM deliver a much higher PCE of up to 17.7%, which is substantially higher than that of devices containing C201 (8.7%) under 100 mW cm(-2) illumination (AM 1.5G). It is revealed that the C202 capping layer exhibits a more homogeneous and uniform surface morphology as compared to that of C201, which effectively reduces the charge recombination losses and facilitates charge extraction, leading to a much-enhanced photovoltaic performance. This is the first example of ICZ core-based small molecules as dopant-free HTMs in PSCs. Moreover, the PSCs containing C202 as the HTM also exhibited good long-term stability under ambient conditions (40% RH) as compared to devices with doped spiro-OMeTAD, due largely to the hydrophobic nature of C202 which prevented moisture from destroying the perovskite film. This work offers a new avenue for developing cost-effective and stable HTMs for PSCs and other optoelectronic devices.
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7.
  • Cai, Bin, et al. (författare)
  • High isotropic dispiro structure hole transporting materials for planar perovskite solar cells
  • 2019
  • Ingår i: Journal of Energy Challenges and Mechanics. - : Elsevier. - 2056-9386. ; 32, s. 152-158
  • Tidskriftsartikel (refereegranskat)abstract
    • Two novel fluorene-based hole transporting materials (HTMs) were synthesized to be used in perovskite solar cells (PSCs). C102 was designed based on C101 by simply linking the two carbon-carbon single bonds to compose a "dispiro" structure. Their typically similar structures cause them sharing almost the same energy levels. However, their photovoltaic performances are quite different due to the small variations. The PSC that contained the "dispiro" structure, C102, reached a power conversion efficiency (PCE) of 17.4%, while the device contained C101, obtained a lower PCE of 15.5%. Electrochemical properties and Photovoltaic characterization of the two materials have been investigated to explain the result. It is shown that C102 has a stronger ability to transport holes and resist the charge recombination. Thus, the dispiro structure should be more appropriate being used as HTM in PSCs. Physics, Chinese Academy of Sciences.
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8.
  • Cai, Bin, et al. (författare)
  • Unveiling the light soaking effects of the CsPbI3 perovskite solar cells
  • 2020
  • Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 472
  • Tidskriftsartikel (refereegranskat)abstract
    • Pure inorganic perovskite of CsPbI3 attracts great attentions due to its excellent thermal stability and more suitable bandgap for tandem solar cells. The power conversion efficiency (PCE) of CsPbI3 perovskite solar cells has swiftly increased to 19.03%. However, extensive researches on the material property and photovoltaic characterization are rather rare in the literatures. In this study, a remarkable light soaking effect is found in the CsPbI3 based perovskite solar cells as the PCE increases from 10.8% to 18.3% after 180 s soaking under AM 1.5G sunlight. Mechanisms behind this reproducible soaking effect have also been studied. It reveals that the depressed dark current caused by a stronger built-in field and the decreased defects density passivated by the photogenerated electrons result in the enhanced PCE after light soaking. Moreover, we carefully characterize that the supposed "HPbI3" should be "DMAPbI(3)" synthesized through anti-solvent vapor recrystallisation method.
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9.
  • Chen, Cheng, et al. (författare)
  • Degradation of Cyanoacrylic Acid-Based Organic Sensitizers in Dye-Sensitized Solar Cells
  • 2013
  • Ingår i: ChemSusChem. - : Wiley-VCH Verlagsgesellschaft. - 1864-5631 .- 1864-564X. ; 6:7, s. 1270-1275
  • Tidskriftsartikel (refereegranskat)abstract
    • Organic dyes have become widely used in dye-sensitized solar cells (DSSCs) because of their good performance, flexible structural modifications, and low costs. To increase the photostability of organic dye-based DSSCs, we conducted a full study on the degradation mechanism of cyanoacrylic acid-based organic sensitizers in DSSCs. The results showed that with the synergy between water and UV light, the sensitizer could desorb from the TiO2 surface and the cyanoacrylic acid unit of the sensitizer was transformed into the aldehyde group. It was also observed that the water content had a great effect on the degradation process. Our experiments conducted using O-18-labeled water demonstrated that the oxygen atom of the aldehyde group identified in the degraded dye came from the solvent water in the DSSCs. Therefore, controlling the water content during DSSC fabrication, good sealing of cells, and filtering the UV light are crucial to produce DSSCs that are more durable and robust.
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10.
  • Chen, Cheng, et al. (författare)
  • Efficient Panchromatic Organic Sensitizers with Dihydrothiazole Derivative as pi-Bridge for Dye-Sensitized Solar Cells
  • 2013
  • Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 5:21, s. 10960-10965
  • Tidskriftsartikel (refereegranskat)abstract
    • Novel organic dyes CC201 and CC202 with dihydrothiazole derivative as pi-bridge have been synthesizedand applied in the DSSCs. With the synergy electron-withdrawing of dihydrothiazole and cyanoacrylic acid, these two novel dyes CC201 and CC202 show excellent response in the region of 500-800 nm. An efficiency as high as 6.1% was obtained for the device fabricated by sensitizer CC202 together with cobalt electrolyte under standard light illumination (AM 1.5G, 100 mW cm(-2)). These two novel D-pi-A panchromatic organic dyes gave relatively high efficiencies except common reported squaraine dyes.
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11.
  • Chen, Cheng, et al. (författare)
  • Highly efficient organic dyes containing a benzopyran ring as a pi-bridge for DSSCs
  • 2013
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 3:31, s. 12688-12693
  • Tidskriftsartikel (refereegranskat)abstract
    • A series of novel organic dyes containing a benzopyran ring as a p-bridge have been designed and applied in dye-sensitized solar cells (DSSCs). This series of dyes show the excellent DSSCs' performance, due to their efficient light-to-photocurrent conversion in the region from 380 nm to 600 nm, with the highest IPCE values exceeding 90%. Through modification of the donor units, an efficiency as high as 7.5% has been achieved under standard light illumination (AM 1.5G, 100 mW cm(-2)) by the dye CC103.
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12.
  • Chen, Ruikui, et al. (författare)
  • Effect of tetrahydroquinoline dyes structure on the performance of organic dye-sensitized solar cells
  • 2007
  • Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 19:16, s. 4007-4015
  • Tidskriftsartikel (refereegranskat)abstract
    • Eleven novel donor acceptor pi-conjugated (D-pi-A) organic dyes have been engineered and synthesized as sensitizers for the application in dye-sensitized solar cells (DSSCs). The electron-donating moieties are substituted tetrahydroquinoline, and the electron-withdrawing parts are cyanoacrylic acid group or cyanovinylphosphonic acid group. Different lengths of thiophene-containing conjugation moieties (thienyl, thienylvinyl, and dithieno[3,2-b;2',3'-d]thienyl) are introduced to the molecules and serve as electron spacers. Detailed investigation on the relationship between the dye structure, photophysical and photoelectrochemical properties, and performance of DSSCs is described here. The bathochromic shift and increase of the molar extinction coefficient of the absorption spectrum are achieved by introduction of larger conjugation moiety. Even small structural changes of dyes result in significant changes in redox energies and adsorption manner of the dyes on TiO2 surface, affecting dramatically the performance of DSSCs based on these dyes. The higher performances are obtained by DSSCs based on the rigid dye molecules, C2 series dyes (Figure 1), although these dyes have lower light absorption abilities relative to other dyes. A maximum solar-to-electrical energy conversion efficiency (eta) of 4.53% is achieved under simulated AM 1.5 irradiation (100 mW/cm(2)) with a DSSC based on C2-2 dye (V-oc = 597 mV, J(sc) = 12.00 mA/cm(2), ff = 0.63). Density functional theory (DFT) calculations have been performed on the dyes, and the results show that electron distribution from the whole molecules to the anchoring moieties occurred during the HOMO-LUMO excitation. The cyanoacrylic acid groups or cyanovinylphosphonic acid group are essentially coplanar with respect to the thiophene units, reflecting the strong conjugation across the thiophene-anchoring groups.
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13.
  • Chen, Ruikui, et al. (författare)
  • Photoinduced intramolecular charge-transfer state in thiophene-π-conjugated donor-acceptor molecules.
  • 2008
  • Ingår i: Journal of Molecular Structure. - : Elsevier BV. - 0022-2860 .- 1872-8014. ; 876:1-3, s. 102-109
  • Tidskriftsartikel (refereegranskat)abstract
    • Novel thiophene-π-conjugated donor-acceptor mols., 5-[2-(1,2,2,4-tetramethyl-1,2,3,4-tetrahydroquinolin-6-yl)-vinyl]-thiophene-2-carbaldehyde (QTC) and (1-cyano-2-{5-[2-(1,2,2,4-tetramethyl-1,2,3,4-tetrahydroquinolin-6-yl)-vinyl]-thiophen-2-yl}-vinyl)-phosphonic acid di-Et ester (QTCP), were designed and synthesized. Combined exptl. and theor. methods were performed to investigate the photoinduced intramol. charge-transfer (ICT) processes of these compds. Steady-state absorption and fluorescence measurements in different solvents indicate the photoinduced ICT characters of QTC and QTCP. Solvent dependency of the large Stokes shifts and high dipole moment of the excited state also support the charge-transfer character of the excited state. Theor. calcns. based on time-dependent d. functional theory (TDDFT) method were performed to investigate ICT states of these compds. The results reveal that the excited states have adopted a distortion of the C=C double bond between the donor moiety and the thiophene-π-bridge. [on SciFinder(R)]
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14.
  • Chen, Ruikui, et al. (författare)
  • Tetrahydroquinoline dyes with different spacers for organic dye-sensitized solar cells
  • 2007
  • Ingår i: Journal of Photochemistry and Photobiology A. - : Elsevier BV. - 1010-6030 .- 1873-2666. ; 189:03-feb, s. 295-300
  • Tidskriftsartikel (refereegranskat)abstract
    • Novel organic dyes (C1-1, C1-5 and C2-1) with a tetrahydroquinoline moiety as the electron donor, different thiophene-containing electron spacers and a cyanoacrylic acid moiety as the electron acceptor have been designed and synthesized for the application in dye-sensitized solar cells (DSSCs). An interesting relationship between the dye structures, properties, and the performance of DSSCs based on these tetrahydroquinoline dyes is obtained. Although C2-1 dye, which has a rigid electron spacer, has the narrowest action spectrum among these dyes, it gives the highest solar-to-electricity conversion efficiency (eta) of 4.49% (V-oc = 600 mV, J(sc) = 11.20 mA/cm(2), ff = 0.67) of a DSSC under simulated AM 1.5 irradiation (100 mW/cm(2)). Under the same conditions, the eta value of a DSSC based on N3 dye is 6.16%.
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15.
  • Cheng, Ming, et al. (författare)
  • A Perylenediimide Tetramer-Based 3D Electron Transport Material for Efficient Planar Perovskite Solar Cell
  • 2017
  • Ingår i: Solar RRL. - : John Wiley & Sons. - 2367-198X. ; 1:5
  • Tidskriftsartikel (refereegranskat)abstract
    • A perylenediimide (PDI) tetramer-based three dimensional (3D) molecular material, termed SFX-PDI4, has been designed, synthesized, and characterized. The low-lying HOMO and LUMO energy levels, high electron mobility and good film-formation property make it a promising electron transport material (ETM) in inverted planar perovskite solar cells (PSCs). The device exhibits a high power conversion efficiency (PCE) of 15.3% with negligible hysteresis, which can rival that of device based on PC61BM. These results demonstrate that three dimensional PDI-based molecular materials could serve as high performance ETMs in PSCs.
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16.
  • Cheng, Ming, et al. (författare)
  • Dye-Sensitized Solar Cells Based on a Donor-Acceptor System with a Pyridine Cation as an Electron-Withdrawing Anchoring Group
  • 2012
  • Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 18:50, s. 16196-16202
  • Tidskriftsartikel (refereegranskat)abstract
    • New hemicyanine dyes (CM101, CM102, CM103, and CM104) in which tetrahydroquinoline derivatives are used as electron donors and N-(carboxymethyl)-pyridinium is used as an electron acceptor and anchoring group were designed and synthesized for dye-sensitized solar cells (DSSCs). Compared with corresponding dyes that have cyanoacetic acid as the acceptor, N-(carboxymethyl)-pyridinium has a stronger electron-withdrawing ability, which causes the absorption maximum of dyes to be redshifted. The photovoltaic performance of the DSSCs based on dyes CM101CM104 markedly depends on the molecular structures of the dyes in terms of the n-hexyl chains and methoxyl. The device sensitized by dye CM104 achieved the best conversion efficiency of 7.0?% (Jsc=13.4 mA?cm-2, Voc=704 mV, FF=74.8?%) under AM 1.5 irradiation (100 mW?cm-2). In contrast, the device sensitized by reference dye CMR104 with the same donor but the cyanoacetic acid as the acceptor gave an efficiency of 3.4?% (Jsc=6.2 mA?cm-2, Voc=730 mV, FF=74.8?%). Under the same conditions, the cell fabricated with N719 sensitized porous TiO2 exhibited an efficiency of 7.9?% (Jsc=15.4 mA?cm-2, Voc=723 mV, FF=72.3?%). The dyes CM101CM104 show a broader spectral response compared with the reference dyes CMR101CMR104 and have high IPCE exceeding 90?% from 450 to 580 nm. Considering the reflection of sunlight, the photoelectric conversion efficiency could be almost 100?% during this region.
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17.
  • Cheng, Ming, et al. (författare)
  • Dye-sensitized solar cells based on hydroquinone/benzoquinone as bio-inspired redox couple with different counter electrodes
  • 2013
  • Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 15:36, s. 15146-15152
  • Tidskriftsartikel (refereegranskat)abstract
    • In the present study, tetramethylammonium hydroquinone (HQ)/benzoquinone (BQ) were developed for use as a redox couple, with poly(3,4-ethylenedioxythiophene) (PEDOT) and multiwalled carbon nanotubes (MWNT) being proposed for use as counter electrode (CE) catalysts in dye-sensitized solar cells (DSSCs). Both metal-complex N719 and metal-free organic dye CM309 were employed to fabricate devices. For the devices sensitized by N719, when using PEDOT and MWNT CEs, power conversion efficiencies (PCE) of 5.2 and 4.9% were obtained, respectively, which were much higher than that of the device using the traditional Pt CE (4.7%) when HQ/BQ electrolyte was employed. However, with the HQ/BQ redox shuttle, the efficiency of the devices sensitized by N719 is much lower than that of the devices when the traditional I-/I-3(-) based electrolyte and Pt CE were employed (7.9%). While for the CM309 sensitized solar cells, when the HQ/BQ redox shuttle was employed, PEDOT and MWNT performed much better than Pt, the DSSC using the PEDOT CE showed an efficiency of 6.2%, which was close to that of the DSSC using the traditional I-/I-3(-) electrolyte and Pt CE (6.3%).
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18.
  • Cheng, Ming, et al. (författare)
  • Effect of the acceptor on the performance of dye-sensitized solar cells
  • 2013
  • Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 15:40, s. 17452-17459
  • Tidskriftsartikel (refereegranskat)abstract
    • Three new phenothiazine dyes were designed and synthesized, utilizing different acceptor groups. Upon application to TiO2-based solar cells, the effects of different acceptors on the photophysical and electrochemical properties of the dyes and the solar cell performance are detailed. The introduction of a pyridinium unit or 5-carboxy-1-hexyl-2,3,3-trimethyl-indolium unit into the molecular frame as the acceptor instead of cyano acrylic acid can effectively cause a red shift in the absorption spectra. Applied to DSSCs, the devices sensitized by CM502 with the pyridinium unit as the acceptor show the highest efficiency of 7.3%. The devices fabricated with dye CM501 with cyano acrylic acid as the acceptor exhibited the highest V-oc while for the devices sensitized by the dye CM503 with 5-carboxy-1-hexyl2,3,3- trimethyl-3H-indolium unit as the acceptor, the Voc value was the lowest, at 494 mV. The addition of TBP in the electrolyte can improve the performance of DSSCs fabricated using CM501 and CM502, with the Voc value greatly improved but the J(sc) value slightly decreased. However, with the addition of TBP in the electrolyte, the efficiency of the cells sensitized by CM503 dropped significantly (from 4.9% to 1.0% when 0.1 M TBP was added).
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19.
  • Cheng, Ming, et al. (författare)
  • Efficient dye-sensitized solar cells based on an iodine-free electrolyte using L-cysteine/L-cystine as a redox couple
  • 2012
  • Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 5:4, s. 6290-6293
  • Tidskriftsartikel (refereegranskat)abstract
    • A new iodine-free electrolyte based on amino acids L-cysteine/L-cystine as a redox couple has been designed and synthesized. DSSCs fabricated with the conventional I-/I-3(-) redox couple gave efficiencies of 8.1% and 6.3% under optimized experimental conditions based on ruthenium dye, N719, and metal-free organic dye, TH202, respectively. Based on the same dyes, the DSSCs employing the new L-cysteine/L-cystine redox couple showed comparable efficiencies of 7.7% and 5.6%, respectively. However, higher incident-photon-to-electron (IPCE) conversion efficiencies and larger J(sc) values were found for devices with the L-cysteine/L-cystine redox couple than with I-/I-3(-). From an electrochemical impedance spectroscopic study, we found that the charge recombination between the conduction band electrons in the TiO2 film and the electrolyte containing the L-cysteine/L-cystine redox couple is restrained.
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20.
  • Cheng, Ming, et al. (författare)
  • Efficient Dye-Sensitized Solar Cells Based on Hydroquinone/Benzoquinone as a Bioinspired Redox Couple
  • 2012
  • Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 51:39, s. 9896-9899
  • Tidskriftsartikel (refereegranskat)abstract
    • A hybrid electrolyte involving tetramethylammonium (TMA) hydroquinone/benzoquinone redox couple is formulated. This electrolyte is more transparent than the traditional I -/I 3 - electrolyte and has negligible absorption in the visible region. Dye-sensitized solar cells using the hybrid electrolyte show higher light-to-electricity conversion efficiency. FTO=fluorine-doped tin oxide.
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21.
  • Cheng, Ming, et al. (författare)
  • Efficient Organic Dye-Sensitized Solar Cells : Molecular Engineering of Donor-Acceptor-Acceptor cationic dyes
  • 2013
  • Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 6:12, s. 2322-2329
  • Tidskriftsartikel (refereegranskat)abstract
    • Three metal-free donor-acceptor-acceptor sensitizers with ionized pyridine and a reference dye were synthesized, and a detailed investigation of the relationship between the dye structure and the photophysical and photoelectrochemical properties and the performance of dye-sensitized solar cells (DSSCs) is described. The ionization of pyridine results in a red shift of the absorption spectrum in comparison to that of the reference dye. This is mainly attributable to the ionization of pyridine increasing the electron-withdrawing ability of the total acceptor part. Incorporation of the strong electron-withdrawing units of pyridinium and cyano acrylic acid gives rise to optimized energy levels, resulting in a large response range of wavelengths. When attached to TiO2 film, the conduction band of TiO2 is negatively shifted to a different extent depending on the dye. This is attributed to the electron recombination rate between the TiO2 film and the electrolyte being efficiently suppressed by the introduction of long alkyl chains and thiophene units. DSSCs assembled using these dyes show efficiencies as high as 8.8%.
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22.
  • Cheng, Ming, et al. (författare)
  • Molecular engineering of small molecules donor materials based on phenoxazine core unit for solution-processed organic solar cells
  • 2014
  • Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488. ; 2:27, s. 10465-10469
  • Tidskriftsartikel (refereegranskat)abstract
    • A D-pi-A type small molecule POZ4 and a A-pi-D-pi-A type small molecule POZ6, in which phenoxazine was used as the central building block and dicyanovinyl was employed as the electron-withdrawing end-group, have been designed and synthesized. Compared with D-pi-A type donor material POZ4, the donor material POZ6 with A-pi-D-pi-A configuration shows much wider response to solar light. An efficiency of 5.60% was obtained for the POZ6: PC71BM based solar cells, and the device fabricated with POZ6:PC71BM (1 : 1) showed a much better balanced hole and electron mobility of 2.24 x 10(-4) cm(2) V-1 s(-1) and 3.17 x 10(-4) cm(2) V-1 s(-1), respectively.
  •  
23.
  • Cheng, Ming, et al. (författare)
  • Novel Small Molecular Materials Based on Phenoxazine Core Unit for Efficient Bulk Heterojunction Organic Solar Cells and Perovskite Solar Cells
  • 2015
  • Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 27:5, s. 1808-1814
  • Tidskriftsartikel (refereegranskat)abstract
    • Two novel Acceptor-Donor-Acceptor (A-D-A) structured small molecular (SM-) materials POZ2 and POZ3 using an electron-rich phenoxazine (POZ) unit as a core building block were designed and synthesized. Their unique characteristics, such as suitable energy levels, strong optical absorption in the visible region, high hole mobility, and high conductivity, prompted us to use them both as p-type donor materials (DMs) in SM-bulk heterojunction organic solar cells (BHJ OSCs) and as hole transport materials (HTMs) in CH3NH3PbI3-based perovskite solar cells (PSCs). The POZ(2)-based devices yielded promising power conversion efficiencies (PCEs) of 7.44% and 12.8% in BHJ OSCs and PSCs, respectively, which were higher than the PCEs of 6.73% (BHJ-OSCs) and 11.5% (PSCs) obtained with the POZ3-based devices. Moreover, our results demonstrated that the POZ2 employing the electron-deficient benzothiazole (BTZ) as linker exhibited higher hole mobility and conductivity than that of the POZ3 using thiophene as linker, leading to better device performance both in BHJ-OSCs and PSCs. These results also provide guidance for the molecular design of high charge carrier mobility SM-materials for highly efficient BHJ OSCs and PSCs in the future.
  •  
24.
  • Cheng, Ming, et al. (författare)
  • Tuning the HOMO and LUMO Energy Levels of Organic Dyes with N-Carboxomethylpyridinium as Acceptor To Optimize the Efficiency of Dye-Sensitized Solar Cells
  • 2013
  • Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:18, s. 9076-9083
  • Tidskriftsartikel (refereegranskat)abstract
    • Different from traditional D-pi-A sensitizers (the traditional design concept of the organic dyes is the donor-pi-linker-acceptor structure), a series of organic dyes with pyridinium as acceptor have been synthesized in order to approach the optimal energy level composition in the TiO2-dye-iodide/triiodide system in the dye-sensitized solar cells. HOMO and LUMO energy level tuning is achieved by varying the conjugation units and the donating ability of the donor part. Detailed investigation on the relationship between the dye structure and photophysical, photoelectrochemical properties and performance of DSSCs is described. For TPA-based dyes, by substituting the 3-hexylthiophene group with a carbon-carbon double bond as pi-spacer, the bathochromic shift of absorption spectra and higher current density (J(sc)) are achieved. When the methoxyl and n-hexoxyl are introduced into CM301 to construct dyes CM302 and CM303, the absorption peak is red-shifted compared with that of CM301 due to the increase of the electron-donating ability. The devices fabricated with sensitizers CM302 and CM303 show higher J(sc) and open-circuit voltage (V-oc) than those of the device sensitized by CM301, which can be mainly attributed to the wider incident photon-to-current conversion efficiency (IPCE) response and the suppression of electron recombination between TiO2 film and electrolyte, respectively. The effects of different electron donors in DSSCs application are compared, and the results show that sensitizers with a phenothiazine (PTZ) electron-donating unit give a promising efficiency, which is even better than the TPA-based dyes. This is because the PTZ unit displayed a stronger electron-donating ability than the TPA unit (oxidation potential of 0.82 and 1.08 V vs the normal hydrogen electrode (NHE), respectively). For sensitizers CM306 and CM307, the introduction of 1,3- bis(hexyloxy)phenyl increases the donating ability of the donor part. Furthermore, the presence of long alkyl chains decreases the dye adsorption amount on the TiO2 surface, which diminishes dye aggregation and the electron recombination effectively, though, with less adsorption amount of dyes on TiO2, the device sensitized by dye CM307 obtained the best conversion efficiency of 7.1% (J(sc) = 13.6 mA.cm(-2), V-oc = 710 mV, FF = 73.6%) under AM 1.5G irradiation (100 mW.cm(-2)).
  •  
25.
  • Cong, Jiayan, et al. (författare)
  • A highly efficient colourless sulfur/iodide-based hybrid electrolyte for dye-sensitized solar cells
  • 2012
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 2:9, s. 3625-3629
  • Tidskriftsartikel (refereegranskat)abstract
    • A new kind of hybrid electrolyte with S2-/S-x(2-) and I- was invented, and the new hybrid system was demonstrated to outperform the well-known I-/I-3(-) redox system in DSCs. An efficiency of 9.1% was achieved in our lab under AM 1.5 illumination using the dye N719, considerably higher than the efficiency of 8.0% of the I-/I-3(-)-based electrolyte.
  •  
26.
  • Cong, Jiayan, et al. (författare)
  • Iodine/iodide-free redox shuttles for liquid electrolyte-based dye-sensitized solar cells
  • 2012
  • Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 5:11, s. 9180-9194
  • Forskningsöversikt (refereegranskat)abstract
    • Dye-sensitized solar cells have attracted intense academic interest over the past two decades. For a long time, the development of new redox systems has fallen far behind that of the sensitizing dyes and other materials. However, the field has received renewed attention recently. In particular, in 2011, the Gratzel group published a record DSC efficiency of 12.3% by using a new Co-complex-based electrolyte. In this review, we will provide an overview of iodine/iodide-free redox systems for liquid electrolytes, and reveal that the design of an efficient redox system should combine with appropriate sensitizing dyes which is the pivotal challenge for highly efficient DSCs.
  •  
27.
  • Cong, Jiayan, et al. (författare)
  • Nitro group as a new anchoring group for organic dyes in dye-sensitized solar cells
  • 2012
  • Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 48:53, s. 6663-6665
  • Tidskriftsartikel (refereegranskat)abstract
    • An organic dye JY1 bearing a nitro group was designed, synthesized and applied in DSCs. An unusual colour change was observed when the voltage applied to the device was reversed which was accompanied by a five-fold increase in the cell efficiency. We propose that applying a bias enabled the attachment of nitro groups to the TiO2 surface.
  •  
28.
  • Han, Siyuan, et al. (författare)
  • Side-chain engineering of PEDOT derivatives as dopant-free hole-transporting materials for efficient and stable n-i-p structured perovskite solar cells
  • 2020
  • Ingår i: Journal of Materials Chemistry C. - : Royal Society of Chemistry (RSC). - 2050-7526 .- 2050-7534. ; 8:27, s. 9236-9242
  • Tidskriftsartikel (refereegranskat)abstract
    • Low-cost poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives have been widely used as hole-transporting materials (HTMs) in p-i-n perovskite solar cells (PSCs). However, reports on the use of PEDOT-based HTMs in regular PSCs have been rather limited up till now due to the low solubility of PEDOT in organic solvents. In this work, we report three PEDOT derivatives, namely, PEDOT-C6 (P6), PEDOT-C10 (P10), and PEDOT-C14 (P14), with a simple synthetic process by tailoring the length of the alkyl side-chains, and apply them as dopant-free HTMs in mesoscopic n-i-p structured PSCs. It is revealed that the alkyl side-chain length has a significant impact on the film morphology, hole transport capability, and thus the overall solar cell performance. The devices with P10 afford a champion PCE of 16.2% at one sun illumination (100 mW cm(-2), AM 1.5G), which is significantly higher compared to those based on P6 (12.1%) and P14 (14.8%) under identical conditions. This has been the highest PCE reported so far for dopant-free PEDOT-based HTMs in conventional PSCs. The greatly enhanced photovoltaic performance observed for the P10-based devices is mainly attributed to the superior film formation property and hole transport capability of P10. Furthermore, the devices utilizing P10 also show excellent ambient stability, retaining 75% of their initial performance at a relative humidity (RH) of 80% after 120 h due to the high moisture resistivity of the HTM. The present work provides a new avenue for further developing low-cost, efficient, and stable HTMs in PSCs in the future.
  •  
29.
  • Hao, Yan, et al. (författare)
  • Can aliphatic anchoring groups be utilised with dyes for p-type dye sensitized solar cells?
  • 2016
  • Ingår i: Dalton Transactions. - : Royal Society of Chemistry. - 1477-9226 .- 1477-9234. ; 45:18, s. 7708-7719
  • Tidskriftsartikel (refereegranskat)abstract
    • A series of novel laterally anchoring tetrahydroquinoline derivatives have been synthesized and investigated for their use in NiO-based p-type dye-sensitized solar cells. The kinetics of charge injection and recombination at the NiO-dye interface for these dyes have been thoroughly investigated using pico-second transient absorption and time-resolved infrared measurements. It was revealed that despite the anchoring unit being electronically decoupled from the dye structure, charge injection occurred on a sub picosecond timescale. However, rapid recombination was also observed due to the close proximity of the electron acceptor on the dyes to the NiO surface, ultimately limiting the performance of the p-DSCs.
  •  
30.
  • Hao, Yan, et al. (författare)
  • Efficient near infrared D-π-A sensitizers with lateral anchoring group for dye-sensitized solar cells.
  • 2009
  • Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; :27, s. 4031-4033
  • Tidskriftsartikel (refereegranskat)abstract
    • A new strategy in which the anchoring group is sepd. from the acceptor groups of the dyes was developed; among these dyes, the HY103 dye gives a max. IPCE value of 86% at 660 nm and an η value of 3.7% in the NIR region reported in DSCs. [on SciFinder(R)]
  •  
31.
  • Hao, Yan, et al. (författare)
  • Engineering of highly efficient tetrahydroquinoline sensitizers for dye-sensitized solar cells
  • 2012
  • Ingår i: Tetrahedron. - : Elsevier. - 0040-4020 .- 1464-5416. ; 68:2, s. 552-558
  • Tidskriftsartikel (refereegranskat)abstract
    • Four novel tetrahydroquinoline dyes by inserting isophorone and/or thiophene moieties as pi bridge between the electron donating unit of substituted tetrahydroquinoline and the electron withdrawing unit of cyano carboxylic acid have been synthesized and successfully applied to dye-sensitized solar cells. Among them, DSCs sensitized by HYTIC, which shows the simplest molecular structure, exhibit improved efficiency of 7.0%. This by now is the highest efficiency for the reported tetrahydroquinoline sensitizers and comparable to the performance of N719-sensitized solar cells under the conditions employed here. (C) 2011 Elsevier Ltd. All rights reserved.
  •  
32.
  • Hao, Yan, et al. (författare)
  • Molecular Design to Improve the Performance of Donor-p Acceptor Near-IR Organic Dye-Sensitized Solar Cells
  • 2011
  • Ingår i: ChemSusChem. - : Wiley-Blackwell. - 1864-5631 .- 1864-564X. ; 4:11, s. 1601-1605
  • Tidskriftsartikel (refereegranskat)abstract
    • Near-dye experience: Long, flexible carbon chains in the lateral anchoring groups of the donor part of a donor-π acceptor organic dye increase the power conversion efficiency dramatically. This performance enhancement can be ascribed to the prevention of the formation of molecular aggregates on the semiconductor nanoparticles, resulting in a lower recombination rate between transported electrons and I3- ions. A cell based on the new dye, HY113, gives a maximum IPCE value of 93% at 660nm.
  •  
33.
  • Hao, Yan, et al. (författare)
  • Photo-induced electron transfer study of D-pi-A sensitizers with different type of anchoring groups for dye-sensitized solar cells
  • 2012
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 2:14, s. 6011-6017
  • Tidskriftsartikel (refereegranskat)abstract
    • A new D-pi-A organic dye HY102 with a lateral anchoring group and two reference dyes HY102-1 (using cyanoacrylic acid as an electron acceptor and the anchoring group) and HY102-2 (containing both cyanoacrylic acid and lateral carboxylic acid) have been synthesized. The optical and electrochemical test results from the three different styles of photosensitizers show that the excited electrons of the novel dye HY102 with lateral carboxylic acid group most probably are injected into the CB of TiO2 through the electron acceptor moiety close to the TiO2 surface by spatial transfer, not through the lateral anchoring group of the carboxylic acid. Research into the photo-induced electron transfer of the novel sensitizers with lateral anchoring system is reasonable and crucial for further improving efficiencies by modifying the molecular structures.
  •  
34.
  • Hu, Maowei, et al. (författare)
  • Efficient and Stable Dye-Sensitized Solar Cells Based on a Tetradentate Copper(II/I) Redox Mediator
  • 2018
  • Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 10:36, s. 30409-30416
  • Tidskriftsartikel (refereegranskat)abstract
    • The identification of an efficient and stable redox mediator is of paramount importance for commercialization of dye-sensitized solar cells (DSCs). Herein, we report a new class of copper complexes containing diamine-dipyridine tetradentate ligands (L1 = N,N'-dibenzyl-N,N'-bis-(pyridin-2-ylmethyl)ethylenediamine; L2 = N,N'-dibenzyl-N,N'-bis (6-methyl-pyridin-2-ylmethyl)ethylenediamine) as redox mediators in DSCs. Devices constructed with [Cu(L2)](2+/+) redox couple afford an impressive power conversion efficiency (PCE) of 9.2% measured under simulated one sun irradiation (100 mW cm(-2), AM 1.5G), which is among the top efficiencies reported thus far for DSCs with copper complex-based redox mediators. Remarkably, the excellent air, photo, and electrochemical stability of the [Cu(L2)](2+/+) complexes renders an outstanding long-term stability of the whole DSC device, maintaining similar to 90% of the initial efficiency over 500 h under continuous full sun irradiation. This work unfolds a new platform for developing highly efficient and stable redox mediators for large-scale application of DSCs.
  •  
35.
  • Jiang, Xiaoqing, et al. (författare)
  • A solution-processable copper(II) phthalocyanine derivative as a dopant-free hole-transporting material for efficient and stable carbon counter electrode-based perovskite solar cells
  • 2017
  • Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 5:34, s. 17862-17866
  • Tidskriftsartikel (refereegranskat)abstract
    • A solution-processable copper(II) phthalocyanine derivative coded as CuPc-TIPS has been synthesized and adopted as a hole-transporting material (HTM) in perovskite solar cells (PSCs), in combination with a mixed-ion perovskite absorber and a low-cost carbon cathode. Optimised PSC devices based on pristine CuPc-TIPS without any additives or dopants show a decent power conversion efficiency of 14.0% (measured at 100 mW cm(-2) illumination, AM 1.5G), together with a good long-termstability under ambient conditions. The present finding highlights the potential of solution-processed copper phthalocyanine derivative-based HTMs for the development of efficient and stable PSCs in the future.
  •  
36.
  • Jiang, Xiao, et al. (författare)
  • Electrogenerated chemiluminescence of a series of donor - Acceptor molecules and X-ray crystallographic evidence for the reaction mechanisms
  • 2007
  • Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 111:26, s. 9595-9602
  • Tidskriftsartikel (refereegranskat)abstract
    • Three series of donor-acceptor pi-conjugated (D-pi-A) molecules 1-3 have been synthesized with a 2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolinyl (Julolidine group), N,N-dimethylamino, or N,N-diphenylamino group as the donor moiety, a phenylvinyl or thienylvinyl unit as the bridge, and a bromide or aldehyde group as the acceptor moiety. The photophysical, electrochemical, and electrogenerated chemiluminescence (ECL) characters of these compounds have been studied in a 1:1 PhH/MeCN solution. Three different categories of ECL mechanisms for each of the three families of compounds are discussed, respectively. Compounds 1a-c produce typical and simple monomer ECL emission resulting from the annihilation of their radical cations and radical anions. The ECL emission of compounds 2a-c can be ascribed as an excimer emission. Compounds 3a-c exhibit an aggregate ECL emission. X-ray crystal structures of compounds 1b, 2a, and 3a provide further proof for the above-mentioned reaction mechanisms. All these compounds show stable ECL emission via the singlet excited state without the addition of any co-reactant or additional compound.
  •  
37.
  • Jiang, Xiao, et al. (författare)
  • Electrogenerated chemiluminescence, of benzo 15-crown-5 derivatives
  • 2009
  • Ingår i: Journal of Physical Organic Chemistry. - : Wiley. - 0894-3230 .- 1099-1395. ; 22:1, s. 1-8
  • Tidskriftsartikel (refereegranskat)abstract
    • Novel electrogenerated chemiluminescence (ECL) reagents C1, C2, and C3 with high fluorescence quantum yields bearing 15-crown-5 moiety have been synthesized and characterized. The photophysical, electrochemical, and ECL characters of these compounds have been studied in a 1:1 (v/v) PhH/MeCN mixed solvent. The ECL intensity is enhanced distinctly with the increase in the fluorescence quantum yield. Their ECL behaviors have been studied using annihilation and co-reactant methods (tri-n-propylamine (TPrA) was used as a co-reactant), respectively. The stable ECL emissions of compounds C1-C3 can be ascribed to the typical and simple monomer ECL emission via S-route.
  •  
38.
  • Jiang, Xiaoqing, et al. (författare)
  • High-Performance Regular Perovskite Solar Cells Employing Low-Cost Poly(ethylenedioxythiophene) as a Hole-Transporting Material
  • 2017
  • Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • Herein, we successfully applied a facile in-situ solid-state synthesis of conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) as a HTM, directly on top of the perovskite layer, in conventional mesoscopic perovskite solar cells (PSCs) (n-i-p structure). The fabrication of the PEDOT film only involved a very simple in-situ solid-state polymerisation step from a monomer 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) made from a commercially available and cheap starting material. The ultraviolet photoelectron spectroscopy (UPS) demonstrated that the as-prepared PEDOT film possesses the highest occupied molecular orbital (HOMO) energy level of -5.5 eV, which facilitates an effective hole extraction from the perovskite absorber as confirmed by the photoluminescence measurements. Optimised PSC devices employing this polymeric HTM in combination with a low-cost vacuum-free carbon cathode (replacing the gold), show an excellent power conversion efficiency (PCE) of 17.0% measured at 100 mW cm(-2) illumination (AM 1.5G), with an open-circuit voltage (V-oc) of 1.05 V, a short-circuit current density (J(sc)) of 23.5 mA/cm(2) and a fill factor (FF) of 0.69, respectively. The present finding highlights the potential application of PEDOT made from solid-state polymerisation as a HTM for cost-effective and highly efficient PSCs.
  •  
39.
  • Jiang, Xiaoqing, et al. (författare)
  • Molecular Engineering of Copper Phthalocyanines : A Strategy in Developing Dopant-Free Hole-Transporting Materials for Efficient and Ambient-Stable Perovskite Solar Cells
  • 2019
  • Ingår i: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 9:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Copper (II) phthalocyanines (CuPcs) have attracted growing interest as promising hole-transporting materials (HTMs) in perovskite solar cells (PSCs) due to their low-cost and excellent stability. However, the most efficient PSCs using CuPc-based HTMs reported thus far still rely on hygroscopic p-type dopants, which notoriously deteriorate device stability. Herein, two new CuPc derivatives are designed, namely CuPc-Bu and CuPc-OBu, by molecular engineering of the non-peripheral substituents of the Pc rings, and applied as dopant-free HTMs in PSCs. Remarkably, a small structural change from butyl groups to butoxy groups in the substituents of the Pc rings significantly influences the molecular ordering and effectively improves the hole mobility and solar cell performance. As a consequence, PSCs based on dopant-free CuPc-OBu as HTMs deliver an impressive power conversion efficiency (PCE) of up to 17.6% under one sun illumination, which is considerably higher than that of devices with CuPc-Bu (14.3%). Moreover, PSCs containing dopant-free CuPc-OBu HTMs show a markedly improved ambient stability when stored without encapsulation under ambient conditions with a relative humidity of 85% compared to devices containing doped Spiro-OMeTAD. This work thus provides a fundamental strategy for the future design of cost-effective and stable HTMs for PSCs and other optoelectronic devices.
  •  
40.
  • Kong, Zhixia, et al. (författare)
  • A new class of organic dyes based on acenaphthopyrazine for dye-sensitized solar cells
  • 2010
  • Ingår i: Journal of Photochemistry and Photobiology A. - : Elsevier BV. - 1010-6030 .- 1873-2666. ; 213:2-3, s. 152-157
  • Tidskriftsartikel (refereegranskat)abstract
    • A new class of organic dyes based on acenaphthopyrazine derivatives, containing pyrazine group as the electron acceptor and o-dicarboxyl acids as the anchoring groups were designed and synthesized for application in dye-sensitized solar cells (DSCs). These dyes have short synthesis routes and are easily adsorbed on the surface of TiO2. Under illumination of simulated AM1.5 solar light (100 mW cm(-2)), a total solar energy conversion efficiency (eta) of 4.04% was obtained for the 3-(diphenylamino)acenaphtho[1,2-b] pyrazine-8,9-dicarboxylic acid (AP-1) in the preliminary tests, in comparison with the conventional N719 dye (eta=7.05%) under the same conditions.
  •  
41.
  • Li, Chaoyan, et al. (författare)
  • Anthraquinone dyes as photosensitizers for dye-sensitized solar cells
  • 2007
  • Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 91:19, s. 1863-1871
  • Tidskriftsartikel (refereegranskat)abstract
    • Three anthraquitione dyes with carboxylic acid as anchoring group are designed and synthesized as sensitizers for dye-sensitized solar cells (DSSCs). Preliminary photophysical and photoelectrochemical measurements show that these anthraquinone dyes have very low performance on DSSC applications, although they have broad and intense absorption spectra in the visible region (up to 800nm). Transient absorption kinetics, fluorescence lifetime measurements and density functional theory (DFT) calculations are conducted to investigate the cause of such low DSSC performance for these dyes. The results show that the strong electron -withdrawing character of the two carbonyl groups on anthraquinone framework may lie behind the low performance by suppressing the efficient electron injection from the dye to the conduction band of TiO2.
  •  
42.
  • Li, Jiajia, et al. (författare)
  • Phenoxazine-based panchromatic organic sensitizers for dye-sensitized solar cells
  • 2015
  • Ingår i: Dyes and pigments. - : Elsevier BV. - 0143-7208 .- 1873-3743. ; 116, s. 58-64
  • Tidskriftsartikel (refereegranskat)abstract
    • A series of metal-free organic dyes LJJ101-LJJ103 composed of phenoxazine unit and indolinum carboxyl acid derivative have been synthesized for dye-sensitized solar cells. A systematic investigation has been conducted for the photology and electrochemistry properties of dyes LJJ101-LJJ103. Panchromatic spectra responses for all the three dyes have been obtained and extended to about 800 nm in near-infrared region. Compared to LJJ101, the introduction of thiophene and squaraine unit causes a red-shift absorption response for LJJ102 and LJJ103, respectively. When applied in dye-sensitized solar cells under AM 1.5 illumination, the device sensitized by LJJ103 yields the best conversion efficiency of 5.1% with a short-circuit photocurrent density of 13.7 mA/cm(2), an open-circuit photovoltage of 502 mV and a fill factor of 74.0%.
  •  
43.
  •  
44.
  • Li, Ling, et al. (författare)
  • Efficient organic dye sensitized solar cells based on modified sulfide/polysulfide electrolyte
  • 2011
  • Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 21:15, s. 5573-5575
  • Tidskriftsartikel (refereegranskat)abstract
    • An energy conversion efficiency of up to 5.24% has been attained, under AM 1.5 G illumination for a new dye-sensitized solar cell using TH305, as a low cost organic dye, ((CH3)(4)N)(2)S/((CH3)(4)N)(2)S-2, as an organic electrolyte and CoS as counter electrode.
  •  
45.
  • Li, Ling, et al. (författare)
  • Electric characteristics of MgO-doped TiO2 nanocrystalline film in dye-sensitized solar cells
  • 2011
  • Ingår i: Application Of Chemical Engineering, Pts 1-3. - : Trans Tech Publications Inc.. - 9783037851210 ; , s. 2106-2109
  • Konferensbidrag (refereegranskat)abstract
    • TiO2 were doped with MgO by thermal hydrolysis, The photoelectrochem. properties of the 1%MgO-doped TiO2 film matched with org. dye TH305 were better than those of the anatase TiO2 film. The conduction band of the MgO doped nanostructured TiO2 synthesized neg. shifted by 60 mV, compared to that of undoped TiO2.
  •  
46.
  • Li, Ling, et al. (författare)
  • Highly Efficient CdS Quantum Dot-Sensitized Solar Cells Based on a Modified Polysulfide Electrolyte
  • 2011
  • Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 133:22, s. 8458-8460
  • Tidskriftsartikel (refereegranskat)abstract
    • A modified polysulfide redox couple, [(CH(3))(4)N](2)S/[(CH(3))(4)N](2)S(n), in an organic solvent (3-methoxypropionitrile) was employed in CdS quantum dot (QD)-sensitized solar cells (QDSSCs), and an unprecedented energy conversion efficiency of up to 3.2% was obtained under AM 1.5 G illumination. The QDs were linked to nanoporous TiO(2) via covalent bonds by using thioglycolic acid, and chemical bath deposition in an organic solvent was then used to prepare the QDSSCs, facilitating high wettability and superior penetration capability of the TiO(2) films. A very high fill factor of 0.89 was observed with the optimized QDSSCs.
  •  
47.
  • Liu, Jing, et al. (författare)
  • Axial anchoring designed silicon-porphyrin sensitizers for efficient dye-sensitized solar cells
  • 2013
  • Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 49:100, s. 11785-11787
  • Tidskriftsartikel (refereegranskat)abstract
    • Using silicon as a central atom of porphyrin allows the introduction of axial ligands, which are not only employed to prevent the aggregation of the macrocycles but also anchor the dyes onto the TiO2 surface. A dye-sensitized solar cell with this porphyrin sensitizer achieved a broad IPCE of around 40-60% between 380 and 670 nm.
  •  
48.
  • Liu, Jing, et al. (författare)
  • Tuning band structures of dyes for dye-sensitized solar cells : effect of different pi-bridges on the performance of cells
  • 2013
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 3:36, s. 15734-15743
  • Tidskriftsartikel (refereegranskat)abstract
    • Three organic dyes (LJ101, LJ102, and LJ103) with different pi-bridges such as thiophene, 3-hexylthiophene and 3, 4-ethyldioxythiophene, were prepared and applied for the dye-sensitized solar cells (DSSCs). The effect of the different pi-bridges on the photovoltaic performance of DSSCs were studied with the aid of quantum chemical calculation and electrochemical-impedance spectroscopy (EIS). The introduction of pi-bridges to construct dyes makes the absorption spectra red shift and enhances the molar extinction coefficient compared to the parent structure of TH305 without pi-conjugated bridge. However, the increasing conjugation length of the molecules decreases the performance of DSSCs, due to the two reduced gaps: one is between the LUMO levels of dyes and the conduction band edge of TiO2, the other one is the energy gap between the HOMO levels of dyes and the redox potential of iodide/triiodide. The conversion efficiencies of DSSCs based on LJ series dyes ranged from 6.1 to 6.4%, which are lower than that of TH305 (7.5%).
  •  
49.
  • Marinado, Tannia, et al. (författare)
  • Influence of π-Conjugation Units in Organic Dyes for Dye-Sensitized Solar Cells
  • 2007
  • Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 111:4, s. 1853-1860
  • Tidskriftsartikel (refereegranskat)abstract
    • Two organic dyes with the general structure donor-conjugated chain-acceptor (D-pi-A) have been investigated as sensitizers for nanocrystalline TiO2 solar cells. The electron donor and acceptor groups were pyrrolidine and cyano acrylic acid, respectively. The conjugated chain of 2-cyano-3-{5-[2-(4-pyrrolidin-1-ylphenyl)vinyl]thiophen-2-yl}acrylic acid contains one phenyl ring and a thiophene unit and is therefore denoted PT, while for 2-cyano-3-{5 -[2-(5-pyrrolidin-1-ylthiophen-2-yl)vinyl]thiophen-2-yl}acrylic acid the phenyl ring is replaced by a second thiophene unit (TT). Solar-to-electrical energy conversion efficiencies under simulated AM 1.5 irradiation (1000 W m(-2)) of 2.3% were obtained for solar cells based on PT but of less than 0.05% for those based on TT. The reasons for the dramatic difference of the efficiencies were analyzed. Photoinduced absorption measurements revealed that the TT dye was not properly regenerated by redox electrolyte after electron injection. This sluggish regeneration is probably due to the 0.3 V less positive HOMO level for TT dye compared to the PT dye, resulting in a lower driving force for regeneration of the oxidized dye by iodide in the electrolyte. In addition, regeneration of the oxidized TT dye and electron injection from the excited TT dye may be poor due to formation of dye aggregates/complexes, as FT-IR measurements show an excess of not properly and/or unidentate bound TT dye molecules instead of bidentate bound PT dye molecules. The results highlight that small structural change of dyes results in significant changes in redox energies and binding features, affecting dramatically the performance of these dyes in dye-sensitized solar cells.
  •  
50.
  • Qu, Jishuang, et al. (författare)
  • Improved performance and air stability of perovskite solar cells based on low-cost organic hole-transporting material X60 by incorporating its dicationic salt
  • 2018
  • Ingår i: Science in China Series B. - : Science Press. - 1674-7291 .- 1869-1870. ; 61:2, s. 172-179
  • Tidskriftsartikel (refereegranskat)abstract
    • The development of an efficient, stable, and low-cost hole-transporting material (HTM) is of great significance for perovskite solar cells (PSCs) from future commercialization point of view. Herein, we specifically synthesize a dicationic salt of X60 termed X60(TFSI)(2), and adopt it as an effective and stable "doping" agent to replace the previously used lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) for the low-cost organic HTM X60 in PSCs. The incorporation of this dicationic salt significantly increases the hole conductivity of X60 by two orders of magnitude from 10(-6) to 10(-4) S cm(-1). The dramatic enhancement of the conductivity leads to an impressive power conversion efficiency (PCE) of 19.0% measured at 1 sun illumination (100 mW cm(-2), AM 1.5 G), which is comparable to that of the device doped with LiTFSI (19.3%) under an identical condition. More strikingly, by replacing LiTFSI, the PSC devices incorporating X60(TFSI)(2) also show an excellent long-term durability under ambient atmosphere for 30 days, mainly due to the hydrophobic nature of the X60(TFSI)(2) doped HTM layer, which can effectively prevent the moisture destroying the perovskite layer. The present work paves the way for the development of highly efficient, stable, and low-cost HTM for potential commercialization of PSCs.
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