| 1. |
- Cheng, Ming, et al.
(författare)
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A Perylenediimide Tetramer-Based 3D Electron Transport Material for Efficient Planar Perovskite Solar Cell
- 2017
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Ingår i: Solar RRL. - : John Wiley & Sons. - 2367-198X. ; 1:5
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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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| 2. |
- Teng, Chao, et al.
(författare)
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Tuning the HOMO Energy Levels of Organic Dyes for Dye-Sensitized Solar Cells Based on Br(-)/Br(3)(-) Electrolytes
- 2010
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 16:44, s. 13127-13138
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Tidskriftsartikel (refereegranskat)abstract
- A series of novel metal free organic dyes TC301-TC310 with relatively high HOMO levels were synthesized and applied in dye sensitized solar cells (DSCs) based on electrolytes that contain Br(-)/Br(3)- and I(-)/I(3)(-) The effects of additive Li(+) ions and the HOMO levels of the dyes have an important influence on properties of the dyes and performance of DSCs The addition of Li(+) ions in electrolytes can broaden the absorption spectra of the dyes on TiO(2) films and shift both the LUMO levels of the dyes and the conduction band of TiO(2) thus leading to the increase of J(sc) and the decrease of V(oc) Upon using Br(-)/Br(3)(-) instead of I(-)/I(3)(-), a large increase of V(oc) is attributed to the enlarged energy difference between the redox potentials of electrolyte and the Fermi level of TiO(2), as well as the suppressed electron recombination Incident photon to current efficiency (IPCE) action spectra, electrochemical impedance spectra, and nanosecond laser transient absorption reveal that both the electron collection yields and the dye regeneration yields ((sic)(r)) depend on the potential difference (the driving forces) between the oxidized dyes and the Br(-)/Br(3)(-) redox couple For the dyes for which the HOMO levels are more positive than the redox potential of Br(-)/Br(3)(-) sufficient driving forces lead to the longer effective electron diffusion lengths and almost the same efficient dye regenerations, whereas for the dyes for which the HOMO levels are similar to the redox potential of Br(-)/Br(3)(-), insufficient driving forces lead to shorter effective electron-diffusion lengths and inefficient dye regenerations
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| 3. |
- Cheng, Ming, et al.
(författare)
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Dye-Sensitized Solar Cells Based on a Donor-Acceptor System with a Pyridine Cation as an Electron-Withdrawing Anchoring Group
- 2012
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 18:50, s. 16196-16202
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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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| 4. |
- Cheng, Ming, et al.
(författare)
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Efficient dye-sensitized solar cells based on an iodine-free electrolyte using L-cysteine/L-cystine as a redox couple
- 2012
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 5:4, s. 6290-6293
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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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| 5. |
- Li, Jiajia, et al.
(författare)
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Phenoxazine-based panchromatic organic sensitizers for dye-sensitized solar cells
- 2015
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Ingår i: Dyes and pigments. - : Elsevier BV. - 0143-7208 .- 1873-3743. ; 116, s. 58-64
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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%.
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| 6. |
- Teng, Chao, et al.
(författare)
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Molecular Design of Anthracene-Bridged Metal-Free Organic Dyes for Efficient Dye-Sensitized Solar Cells
- 2010
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:19, s. 9101-9110
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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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| 7. |
- Yang, Xichuan, et al.
(författare)
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A new type of organic sensitizers with pyridine-N-oxide as the anchoring group for dye-sensitized solar cells
- 2013
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 3:33, s. 13677-13680
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Tidskriftsartikel (refereegranskat)abstract
- A series of organic dyes with alkaline pyridine-N-oxide as the electron acceptor and anchoring group have been synthesized and applied in dye-sensitized solar cells. Photoelectrical data show a good coordination between pyridine-N-oxide and TiO2 films, which effectively guarantee the injection and adsorption of the dye molecules. With the simple WL102 dye, the best photon-to-electron conversion efficiency of 3.72% and an excellent IPCE value about 95% have been achieved under optimized conditions.
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| 8. |
- Zhang, Fuguo, et al.
(författare)
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Engineering of hole-selective contact for low temperature-processed carbon counter electrodebased perovskite solar cells
- 2015
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 3:48, s. 24272-24280
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Tidskriftsartikel (refereegranskat)abstract
- A cost-effective and solution processable hole transport material (HTM), TPDI (5,10,15-triphenyl-5H-diindolo[3,2-a:3',2'-c]carbazole), was synthesized and explored as a hole selective contact material in low temperature (100 degrees C) and printable processed carbon counter electrode based perovskite solar cells (PSCs) for the first time. This material demonstrated excellent thermal stability, high hole mobility and appropriate energy level alignment with CH3NH3PbI3 and carbon, which make it a potentially excellent alternative interfacial material for PSCs. By interfacial engineering with doped TPDI, the energy barrier at the CH3NH3PbI3/carbon interface was efficiently eliminated. Dramatically enhanced power conversion efficiency (PCE) of 15.5% was afforded, which is comparable to or even better than that of the reference device with 2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) as HTM under equivalent conditions. Besides, TPDI can also function well in its pristine form although the efficiency (13.6%) obtained is slightly lower than that with the device containing doped TPDI as the HTM. Moreover, these newly integrated noble metal-free, vacuum-free and cost effective PSCs exhibited excellent durability during the long term stability measurements for 30 days. The remarkable performance as well as dramatically reduced fabrication cost demonstrated by integrating TPDI as the HTM and cost effective commercial carbon as the cathode revealed their great potential in the scalable and practical application of PSCs.
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| 9. |
- Zhao, Jianghua, et al.
(författare)
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Highly efficient iso-quinoline cationic organic dyes without vinyl groups for dye-sensitized solar cells
- 2013
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 1:7, s. 2441-2446
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Tidskriftsartikel (refereegranskat)abstract
- Four organic dyes without a vinyl group are synthesized and applied in dye-sensitized solar cells (DSSCs). The iso-quinoline cation is employed firstly as an electron acceptor in the dye molecular structure. The effect of different dye structures on the photo-electrochemical properties and the performance of the DSSCs are systematically studied. The photovoltaic performances of the DSSCs sensitized by the JH304 dye exhibit the best conversion efficiency of 7.3% (under standard AM 1.5G illumination (100 mW cm(-2))) with a short-circuit current density (J(sc)) of 14.4 mA cm(-2), an open-circuit voltage (V-oc) of 684 mV and a fill factor (ff) of 74.4%. In comparison, the device sensitized by the N719 dye shows an efficiency of 7.9%. The DSSC device sensitized by JH304 also exhibits excellent soaking stability under sunlight for 1000 h.
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| 10. |
- Zhao, Jianghua, et al.
(författare)
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Molecular Design and Performance of Hydroxylpyridium Sensitizers for Dye-Sensitized Solar Cells
- 2013
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 5:11, s. 5227-5231
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Tidskriftsartikel (refereegranskat)abstract
- Four hydroxylpyridium organic dyes were synthesized and applied in dye-sensitized solar cells (DSSCs). Hydroxylpyridium was introduced as an electron acceptor in donor-pi-conjugated bridge-acceptor (D-pi-A) system. The traditional anchoring groups, such as the carboxyl group, were replaced by hydroxyl group. It was found that the existence of the hydroxylpyridium exhibits a large effect on the absorption spectra of dyes JH401-JH404. For JH series of dyes, hexylthiophene was employed as the pi-conjugated bridge, and triphenylamine, phenothiazine, and their derivatives were used as the electron donor. The performances of the dyes with different structure were investigated by photophysical, photovoltaic, and electrochemical methods. When applied in the DSSCs, the sensitizer JH401 yields the best efficiency, 2.6% (J(sc) = 6.35 mA/cm(2), V-oc = 605 mV, FF = 67.696) under 100 mW/cm(2) light illumination. Its maximum incident photon-to-current conversion efficiency (IPCE) is 80% at 440 nm light wavelength, which is the highest IPCE value achieved with hydroxyl group adsorbent organic dyes so far.
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