| 1. |
- Chen, Long, et al.
(författare)
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5,6-Bis(octyloxy)benzo[c][1,2,5]thiadiazole-Bridged Dyes for Dye-Sensitized Solar Cells with High Open-Circuit Voltage Performance
- 2013
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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :9, s. 1770-1780
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Tidskriftsartikel (refereegranskat)abstract
- Three new metal-free dyes with a 5,6-bis(octyloxy) benzo[c][1,2,5] thiadiazole core (DOBT-I-III) have been designed and synthesized for use as DSSCs. Their absorption properties and electrochemical and photovoltaic performances have been investigated systematically. The DSSCs based on DOBT-I-III show high open-circuit voltages (V-oc) of 829, 818, and 784 mV, respectively. Of the three dyes, DOBT-III, which contains a thiophene-bridging linker, exhibits the best photovoltaic performance: a short-circuit photocurrent density (J(sc)) of 12.74 mA cm(-2) and a fill factor (FF) of 0.73, which corresponds to an overall conversion efficiency of 7.29% under standard global AM 1.5 solar conditions.
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| 2. |
- Freitag, Marina, et al.
(författare)
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Dye-sensitized solar cells for efficient power generation under ambient lighting
- 2017
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Ingår i: Nature Photonics. - : NATURE PUBLISHING GROUP. - 1749-4885 .- 1749-4893. ; 11:6, s. 372-
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Tidskriftsartikel (refereegranskat)abstract
- Solar cells that operate efficiently under indoor lighting are of great practical interest as they can serve as electric power sources for portable electronics and devices for wireless sensor networks or the Internet of Things. Here, we demonstrate a dye-sensitized solar cell (DSC) that achieves very high power-conversion efficiencies (PCEs) under ambient light conditions. Our photosystem combines two judiciously designed sensitizers, coded D35 and XY1, with the copper complex Cu(II/I)(tmby) as a redox shuttle (tmby, 4,4', 6,6'-tetramethyl-2,2'-bipyridine), and features a high open-circuit photovoltage of 1.1 V. The DSC achieves an external quantum efficiency for photocurrent generation that exceeds 90% across the whole visible domain from 400 to 650 nm, and achieves power outputs of 15.6 and 88.5 mu W cm(-2) at 200 and 1,000 lux, respectively, under illumination from a model Osram 930 warm-white fluorescent light tube. This translates into a PCE of 28.9%.
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| 3. |
- Hao, Yan, et al.
(författare)
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Efficient Dye-Sensitized Solar Cells with Voltages Exceeding 1 V through Exploring Tris(4-alkoxyphenyl)amine Mediators in Combination with the Tris(bipyridine) Cobalt Redox System
- 2018
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 3:8, s. 1929-1937
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Tidskriftsartikel (refereegranskat)abstract
- Tandem redox electrolytes, prepared by the addition of a tris(p-anisyl)amine mediator into classic tris(bipyridine)cobalt-based electrolytes, demonstrate favorable electron transfer and reduced energy loss in dye-sensitized solar cells. Here, we have successfully explored three tris(4-alkoxyphenyl)-amine mediators with bulky molecular structures and generated more effective tandem redox systems. This series of tandem redox electrolytes rendered solar cells with very high photovoltages exceeding 1 V, which approaches the theoretical voltage limit of tris(bipyridine)cobalt-based electrolytes. Solar cells with power conversion efficiencies of 9.7-11.0% under 1 sun illumination were manufactured. This corresponds to an efficiency improvement of up to 50% as compared to solar cells based on pure tris(bipyridine)cobalt-based electrolytes. The photovoltage increases with increasing steric effects of the tris(4-alkoxyphenyl)amine mediators, which is attributed to a retarded recombination kinetics. These results highlight the importance of structural design for optimized charge transfer at the sensitized semiconductor/electrolyte interface and provide insights for the future development of efficient dye-sensitized solar cells.
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| 4. |
- Jiang, Tao, et al.
(författare)
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Tetraphenylethene end-capped diketopyrrolopyrrole fluorogens with AIE and large two-photon absorption cross-sections features and application in bioimaging
- 2016
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Ingår i: Dyes and pigments. - : Elsevier. - 0143-7208 .- 1873-3743. ; 133, s. 201-213
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Tidskriftsartikel (refereegranskat)abstract
- In this work, a series of new diketopyrrolopyrrole-based dyes have been synthesized by connecting tetraphenylethene to the diketopyrrolopyrrole core. All the four compounds exhibit good aggregation induced emission property with nonemissive in the solution but strong red fluorescence in the aggregate or solid state. Also, these new dyes exhibit large two-photon absorption cross sections (a), in which the a data measured by the open aperture Z-scan technique are determined to be 150, 300, 1140 and 1016 GM for four dyes, respectively. In addition, compound with stilbene and four tetraphenylethene units (DPP-TPE-3) was used as the luminogen and encapsulated into nanoparticles for cell imaging and two-photon excited fluorescence blood vessels imaging. The result indicates that it can be used as the effective fluorescence probe for bioimaging and has great potential for bioapplications. (C) 2016 Elsevier Ltd. All rights reserved.
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| 5. |
- Li, Xing, et al.
(författare)
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Enhanced Photocurrent Density by Spin-Coated NiO Photocathodes for N-Annulated Perylene-Based p-Type Dye-Sensitized Solar Cells
- 2016
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 8:30, s. 19393-19401
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Tidskriftsartikel (refereegranskat)abstract
- The low photocurrent density of p-type dye sensitized solar cells (p-DSSCs) has limited the development of high-efficiency tandem cells due to the inadequate light harvesting ability of sensitizers and the low hole mobility of semiconductors. Hereby, two new "push-pull" type organic dyes (PQ-1 and PQ-2) containing N-annulated perylene as electron donor have been synthesized, where the PQ-2-based p-DSSCs show higher photoelectric conversion efficiency (PCE) of 0.316% owing to the higher molar extinction compared to of that PQ-1. Additionally, the photocurrent densities were remarkably increased from 2.20 to 5.85 mA cm(-2) for PQ-1 and 2.45 to 6.69 mA cm(-2) for PQ-2 by spin coated NiO photocathode based-p-DSSCs, respectively. This results are ascribed to the enhancement of hole transport rate, dye loading amounts and transparency of NiO films in comparison to that prepared by screen-printing method. Electrochemical impedance spectroscopy and theoretical calculations studies indicate that the molecular dipole moment approaching closer to the NiO surface shifts the quasi-Fermi level to more positive levels, improving,open-circuit voltage (V-oc). Intensity-modulated photocurrent spectroscopy illustrates that the hole transit time in NiO films prepared in spin-coating is shorter than that prepared by screen-printing method.
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| 6. |
- Li, Xing, et al.
(författare)
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Molecular engineering of D-A-pi-A sensitizers for highly efficient solid-state dye-sensitized solar cells
- 2017
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Ingår i: Journal of Materials Chemistry A. - : RSC Publishing. - 2050-7488 .- 2050-7496. ; 5:7, s. 3157-3166
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Tidskriftsartikel (refereegranskat)abstract
- Two newquinoxaline-based D-A-pi-A organic sensitizers AQ309 and AQ310 have been designed and synthesized employing 3,4-ethylenedioxythiophene (EDOT) and cyclopentadithiophene (CPDT) as plinker units, respectively. The new AQ309 and AQ310 dyes have been applied in all-solid-state dye-sensitized solar cells (ssDSSCs). An impressive record photoelectric conversion efficiency (PCE) of 8.0% for AQ310-based ssDSSCs using Spiro-OMeTAD as the hole transport material (HTM) was obtained under standard AM 1.5 (100 mW cm (2)) solar intensity. This clearly outperforms the PCE of the state-of-theart organic D-pi-A dye LEG4-based devices showing a PCE of 7.3% under the same conditions. Moreover, an excellent high PCE of 8.6% was also recorded for AQ310-based devices under 50% solar intensity. Meanwhile, the AQ310-based ssDSSCs showed a much longer electron lifetime according to the transient photovoltage decay measurement, demonstrating lower charge recombination losses in the devices. Photo-induced absorption spectroscopy (PIA) indicated that AQ310 could be more efficiently regenerated by Spiro-OMeTAD. These results show that molecular engineering is a promising strategy to develop D-A-pi-A organic sensitizers for highly efficient ssDSSCs.
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| 7. |
- Li, Zhong-Yu, et al.
(författare)
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Restricted Rotation of sigma-Bonds through a Rigidified Donor Structure to Increase the ICT Ability of Platinum-Acetylide-Based DSSCs
- 2013
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Ingår i: Chemistry - An Asian Journal. - : Wiley. - 1861-4728 .- 1861-471X. ; 8:11, s. 2660-2669
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Tidskriftsartikel (refereegranskat)abstract
- A series of new triarylamine-based platinum-acetylide complexes (WYs) have been designed and synthesized as new sensitizers for applications in dye-sensitized solar cells (DSSCs). With the aim of investigating the effect of a rigidifying donor structure on the photoelectrical parameters of the corresponding DSSCs, two new sensitizers, WY1 and WY2, with rigid and coplanar fluorene units as an electron donor, were prepared. Moreover, two sensitizers that contained triphenylamine units as an electron donor, WY3 and WY4, were also synthesized for comparison. The photo- and electrochemical properties of all of these new complexes have been extensively explored. We found that the dimethyl-fluorene unit exhibited a stronger electron-donating ability and better photovoltaic performance compared to the triphenylamine unit, owing to its rigidifying structure, which restricted the rotation of sigma bonds, thus increasing the conjugation efficiency. Furthermore, WY2, which contained a dimethyl-fluorene unit as an electron donor and bithiophene as a bridge, showed a relatively high open-circuit voltage (V-oc) of 640mV and a PCE of 4.09%. This work has not only expanded the choice of platinum-acetylide sensitizers, but also demonstrates the advantages of restricted rotation of donor sigma bonds for improved behavior of the corresponding DSSCs.
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| 8. |
- Ma, Xuemei, et al.
(författare)
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Novel fluoranthene dyes for efficient dye-sensitized solar cells
- 2009
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Ingår i: Dyes and pigments. - : Elsevier BV. - 0143-7208 .- 1873-3743. ; 82:3, s. 353-359
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Tidskriftsartikel (refereegranskat)abstract
- Three, novel, fluoranthene-based dyes, 2-cyano-3-(5-(7,12-diphenylbenzo[k]fluoranthen-3-yl)thiophen-2-yl)acryli c acid, 2-(5-((5-(7,12-diphenylben-zo[k]fluoranthen-3-yl)thiophen-2-yl)methylene )-4-oxo-2-thioxothiazolidin-3-yl)acetic acid and 2-cyano-3-(4-(2-(7,12-diphenylbenzo[k]fluoranthen-3-yl)ethynyl)phenyl) acrylic acid, were synthesized for application as sensitizers in dye-sensitized solar cells. In each dye, the 7,12-diphenyl-benzo[k]fluoranthene moiety acted as electron donor with phenyl and thiophene units as electron spacers and carboxylic acid as electron acceptor. Tuning of the HOMO and LUMO energy levels was conveniently accomplished by changing the spacer and acceptor moiety, as confirmed using electrochemical measurements. Maximum solar energy:electricity conversion efficiency was 4.4% under AM 1.5 solar simulator (100 mW cm(-2)) for 2-cyano-3-(5-(7,12-diphenylbenzo[k]fluoranthen-3-yl)thiophen-2-yl)acryli c acid. The results suggest that dyes based on fluoranthene donor are promising candidates for high performance, dye-sensitized solar cells.
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| 9. |
- Shen, Zhongjin, et al.
(författare)
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Synthesis and Photovoltaic Properties of Powerful Electron-Donating Indeno[1, 2-b]thiophene-Based Green D-A-pi-A Sensitizers for Dye-Sensitized Solar Cells
- 2016
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:6, s. 3518-3525
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Tidskriftsartikel (refereegranskat)abstract
- Three new near-infrared D-A-pi-A dyes (Si, S2, and S3) with 80 indeno[1,2-b]thiophene-based strong donor, containing 5,6-difluorobenzo[c][1,2,5]thiadiazole (DFBT), benzo[c][1,2,5]thiadiazole (BT), and 2,3diphenylpyrido[3,4-b]pyrazine (PP) as the auxiliary acceptor, respectively, were synthesized for the application of dye-sensitized solar cells. Introduction of powerful electron-donating unit of indeno[1,2-b]thiophene and the strong electron-withdrawing DFBT, BT, and PP groups into the conjugation bridge can enhance the absorption wavelength range into NIR region, where the maximum absorptions of the three compounds are all over 610 nm and S3 can reach 628 nm. Moreover, it is rare to see that the colors of the dyes are all green both in dichloromethane and on the TiO2 film. Via fine-tuning of the auxiliary moiety, the onset of incident-photon-conversion efficiency of S1-S3 can reach 850 nm and S3-based DSSCs in the presence of iodine and cobalt electrolytes show the best overall solar energy conversion efficiency of 6.29% and 7.23% under full sunlight (AM 1.5G, 100 mW cm(-2)) irradiation, which are relatively high values in organic NIR green dye-based DSSCs. Electrochemical impedance spectroscopy indicates that S3-based DSSCs can suppress charge recombination more efficiently, accounting for its higher open circuit voltage and short circuit current.
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| 10. |
- Wu, Zhifang, et al.
(författare)
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Effect of bridging group configuration on photophysical and photovoltaic performance in dye-sensitized solar cells
- 2015
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Ingår i: Journal of Materials Chemistry A. - : RSC Publishing. - 2050-7488 .- 2050-7496. ; 3:27, s. 14325-14333
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Tidskriftsartikel (refereegranskat)abstract
- Three new metal-free organic sensitizers with a D-A-p-A configuration based on a triarylamine donor, 2,1,3-benzothiadiazole (BTD) and different pi units have been synthesized. Because a long alkyl side chain has been attached to the thiophene adjacent to BDT, HECA achieves the best performance. Under standard global AM 1.5 solar light conditions, the HECA based-device gives the best conversion efficiency of 9.13% with a J(sc) of 16.14 mA cm(-2), a V-oc of 0.72 V and a FF of 0.77. Although EDCA displays superior optical properties, it does not give the desired results. The device based on EDCA achieves efficiency of 7.37% with a J(sc) of 15.56 mA cm(-2), a V-oc of 0.67 V and a FF of 0.70. EIS analysis confirms the existence of fast recombination in the EDCA system. Further computational analysis indicates that the coplanarity and the very strong affinity to iodine molecules of EDCA may be the origin of the low performance.
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