| 1. |
- Abdelhamid, Hani Nasser, et al.
(författare)
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Towards implementing hierarchical porous zeolitic imidazolate frameworks in dye-sensitized solar cells
- 2019
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Ingår i: Royal Society Open Science. - : Royal Society Publishing. - 2054-5703. ; 6:7
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Tidskriftsartikel (refereegranskat)abstract
- A one-pot method for encapsulation of dye, which can be applied for dye-sensitized solar cells (DSSCs), and synthesis of hierarchical porous zeolitic imidazolate frameworks (ZIF-8), is reported. The size of the encapsulated dye tunes the mesoporosity and surface area of ZIF-8. The mesopore size, Langmuir surface area and pore volume are 15 nm, 960-1500 m(2). g(-1) and 0.36-0.61 cm(3). g(-1), respectively. After encapsulation into ZIF-8, the dyes show longer emission lifetimes (greater than 4-8-fold) as compared to the corresponding non-encapsulated dyes, due to suppression of aggregation, and torsional motions.
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| 2. |
- Chen, Cheng, et al.
(författare)
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Cu(II) Complexes as p-Type Dopants in Efficient Perovskite Solar Cells
- 2017
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 2:2, s. 497-503
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Tidskriftsartikel (refereegranskat)abstract
- In this work, two Cu(II) complex compounds are designed and synthesized for applications as p-type dopants in solid-state perovskite solar cells (PSCs). Through the characterization of the optical and electrochemical properties, the complex Cu(bpcm)(2) is shown to be eligible for oxidization of the commonly used hole-transport material (HTM) SpiroOMeTAD. The reason is the electron-withdrawing effect of the chloride groups on the ligands. When the complex was applied as p-type dopant in PSCs containing Spiro-OMeTAD as HTM, an efficiency as high as 18.5% was achieved. This is the first time a Cu(II) pyridine complex has been used as p-type dopant in PSCs.
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| 3. |
- Cong, Jiayan, et al.
(författare)
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A highly efficient colourless sulfur/iodide-based hybrid electrolyte for dye-sensitized solar cells
- 2012
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 2:9, s. 3625-3629
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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.
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| 4. |
- Cong, Jiayan, et al.
(författare)
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Bis(1,1-bis(2-pyridyl)ethane)copper(i/II) as an efficient redox couple for liquid dye-sensitized solar cells
- 2016
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 4:38, s. 14550-14554
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Tidskriftsartikel (refereegranskat)abstract
- A new redox couple, [Cu(bpye)2]+/2+, has been synthesized, and applied in dye-sensitized solar cells (DSSCs). Overall efficiencies of 9.0% at 1 sun and 9.9% at 0.5 sun were obtained, which are considerably higher than those obtained for cells containing the reference redox couple, [Co(bpy)3]2+/3+. These results represent a record for copper-based complex redox systems in liquid DSSCs. Fast dye regeneration, sluggish recombination loss processes, faster electron self-exchange reactions and suitable redox potentials are the main reasons for the observed increase in efficiency. In particular, the main disadvantage of cobalt complex-based redox couples, charge-transport problems, appears to be resolved by a change to copper complex redox couples. The results make copper complex-based redox couples very promising for further development of highly efficient DSSCs.
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| 5. |
- Cong, Jiayan, et al.
(författare)
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Bis(1,1-bis(2-pyridyl)ethane)copper(I/II) as an efficient redox couple for liquid dye-sensitized solar cells
- 2016
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Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 4:38, s. 14550-14554
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Tidskriftsartikel (refereegranskat)abstract
- A new redox couple, [Cu(bpye)2]+/2+, has been synthesized, and applied in dye-sensitized solar cells (DSSCs). Overall efficiencies of 9.0% at 1 sun and 9.9% at 0.5 sun were obtained, which are considerably higher than those obtained for cells containing the reference redox couple, [Co(bpy)3]2+/3+. These results represent a record for copper-based complex redox systems in liquid DSSCs. Fast dye regeneration, sluggish recombination loss processes, faster electron self-exchange reactions and suitable redox potentials are the main reasons for the observed increase in efficiency. In particular, the main disadvantage of cobalt complex-based redox couples, charge-transport problems, appears to be resolved by a change to copper complex redox couples. The results make copper complex-based redox couples very promising for further development of highly efficient DSSCs.
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| 6. |
- Cong, Jiayan, et al.
(författare)
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Electrolytes Based on TEMPO-Co Tandem Redox Systems Outperform Single Redox Systems in Dye-sensitized Solar Cells
- 2015
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 8:2, s. 264-268
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Tidskriftsartikel (refereegranskat)abstract
- A new TEMPO-Co tandem redox system with TEMPO and Co(bpy)(3)(2+/3+) has been investigated for the use in dye-sensitized solar cells (DSSCs). A large open-circuit voltage (V-OC) increase, from 862 mV to 965 mV, was observed in the tandem redox system, while the short-circuit current density (J(SC)) was maintained. The conversion efficiency was observed to increase from 7.1% for cells containing the single Co(bpy)(3)(2+/3+) redox couple, to 8.4% for cells containing the TEMPO-Co tandem redox system. The reason for the increase in V-OC and overall efficiency is ascribed to the involvement of partial regeneration of the sensitizing dye molecules by TEMPO. This assumption can be verified through the observed much faster regeneration dynamics exhibited in the presence of the tandem system. Using the tandem redox system, the faster recombination problem of the single TEMPO redox couple is resolved and the mass-transport of the metal-complex-based electrolyte is also improved. This TEMPO-Co tandem system is so far the most effienct tandem redox electrolyte reported not involving iodine. The current results show a promising future for tandem system as replacements for single redox systems in electrolytes for DSSCs.
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| 7. |
- Cong, Jiayan, et al.
(författare)
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Iodine/iodide-free redox shuttles for liquid electrolyte-based dye-sensitized solar cells
- 2012
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 5:11, s. 9180-9194
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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.
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| 8. |
- Cong, Jiayan, et al.
(författare)
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Nitro group as a new anchoring group for organic dyes in dye-sensitized solar cells
- 2012
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 48:53, s. 6663-6665
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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.
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| 9. |
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| 10. |
- El-Zohry, Ahmed M., et al.
(författare)
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Ferrocene as a rapid charge regenerator in dye-sensitized solar cells
- 2016
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Ingår i: Dyes and pigments. - : Elsevier. - 0143-7208 .- 1873-3743. ; 132, s. 360-368
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Tidskriftsartikel (refereegranskat)abstract
- Using the reductive power of the ferrocene moiety (Fc), an ultrafast regeneration step via a covalent attachment of a Fc moiety to an organic triphenylamine-based dye (L1) when adsorbed on TiO2 is highlighted. Two modified dyes with one and two Fc moieties attached (L1Fc, and L1Fc2), respectively, were synthesized by addition to the L1 dye. These dyes have been studied spectroscopically using ultrafast transient absorption spectroscopy in the visible and the infrared (IR) regions. In acetonitrile, the results show an ultrafast excited state quenching of the modified dyes due to an expected electron transfer process from the Fc(s) to L1. Adsorbed onto TiO2, an electron transfer process is also detected from Fc to the oxidized dye (L1(+)). Despite the occurrence of an ultrafast regeneration step, the solar cell performance does not improve by the attachment of Fc(s) to the dye L1. Transient absorption measurements in the IR region revealed a fast electron recombination process to the Fc(+) moiety on an average time scale of ca. 300 ps, outcompeting the >12 ns process to L1(+). The reasons for the observed considerably faster recombination rate to Fc(+) than to L1(+) are discussed in detail. This study provides deep spectroscopic insights for such organic dyes utilized to afford ultrafast regeneration step without showing high performance in photovoltaic devices. In addition, this study will improve our understandings for the triangular relationship between the molecular design, electron kinetics, and the performance in photovoltaic devices. (C) 2016 Elsevier Ltd. All rights reserved.
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