| 1. |
- Wu, Mingxing, et al.
(författare)
-
Two flexible counter electrodes based on molybdenum and tungsten nitrides for dye-sensitized solar cells
- 2011
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 21:29, s. 10761-10766
-
Tidskriftsartikel (refereegranskat)abstract
- Two novel flexible counter electrodes (CEs) on Ti sheets using molybdenum and tungsten nitrides (Mo(2)N, W(2)N) as catalysts were synthesized and used in a dye-sensitized solar cell (DSC) system. High catalytic activity of the two nitride CEs for the reduction of triiodide were proved by cyclic voltammetry, electrochemical impedance spectroscopy and Tafel-polarization measurements. The DSCs based on Mo(2)N and W(2)N CEs achieved power conversion efficiencies of 6.38 and 5.81%, reaching 91 and 83% of the photovoltaic performance of the DSC using a Pt CE, respectively. This research paves a promising way to develop new CE catalysts and reduce the cost of DSCs.
|
|
| 2. |
- Guo, Wei, et al.
(författare)
-
Highly efficient dye-sensitized solar cells based on nitrogen-doped titania with excellent stability
- 2011
-
Ingår i: Journal of Photochemistry and Photobiology A. - : Elsevier BV. - 1010-6030 .- 1873-2666. ; 219:2-3, s. 180-187
-
Tidskriftsartikel (refereegranskat)abstract
- A series of nitrogen-doped and undoped TiO2 nanocrystals was prepared by several simple methods. Needle-like N-doped TiO2 nanocrystals and nanoparticles were obtained from commercial TiO2 powders. Several dye-sensitized solar cells (DSCs) were fabricated based on N-doped and undoped TiO2 electrodes. The N-doped DSCs achieved a high conversion efficiency of 10.1% and 4.8% using an organic electrolyte and an ionic liquid electrolyte, respectively. Systemic investigations were carried out on the properties of N-doped and undoped TiO2 powders, films, and DSCs. The electron transport time and electron lifetime were investigated by intensity-modulated photocurrent and photovoltage spectroscopy (IMPS/IMVS). Moreover, the electron injection of N-doped DSCs was studied by surface photovoltage spectroscopy (SPS). The synergetic effect of higher dye uptake, faster electron transport and higher photovoltage contributes to a higher conversion efficiency of N-doped DSCs. The stability test also demonstrated that the photodegradation of the DSCs was not accelerated and the DSC system was stabilized by the introduction of nitrogen into the TiO2 photoelectrode. These results indicate that the N-doped TiO2 nanocrystals prepared by our approach from commercial TiO2 are ideal semiconductor materials for DSCs.
|
|
| 3. |
- Guo, Wei, et al.
(författare)
-
Influence of nitrogen dopants on N-doped TiO2 electrodes and their applications in dye-sensitized solar cells
- 2011
-
Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 56:12, s. 4611-4617
-
Tidskriftsartikel (refereegranskat)abstract
- Three different types of nanocrystalline, N-doped TiO2 electrodes were synthesized using several nitrogen dopants through wet methods. The obtained nanocrystalline, N-doped TiO2 electrodes possessed different crystallite sizes, surface areas, and N-doping amounts. Characterizations were performed to reveal the nitrogen-doping processes for the wet methods using ammonia, urea, and triethylamine as the nitrogen dopants. Additionally, a high conversion efficiency of 8.32% was achieved by the dye-sensitized solar cells, based on the N-doped TiO2 electrodes. For instance, in comparison with the commercial P25 (5.76%) and pure anatase TiO2 electrodes (7.14%), significant improvements (44% and 17%, respectively) in the efficiencies were obtained. The findings also indicated that the ammonia nitrogen dopant was more efficient than other two nitrogen dopants. The electron transports, electron lifetimes, and charge recombination in the dye-sensitized N-doped TiO2 solar cells also differed from those in the pure TiO2-based dye-sensitized solar cells (DSCs). Specifically, an enhanced photocurrent of ca. 36% in N-doped DSCs resulted from the synergistic effects of the high dye uptake and the efficient electron transport. Moreover, the relationship between charge and voltage revealed that less charge was needed to get a high open-circuit voltage in the N-doping films.
|
|
| 4. |
- 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.
|
|
| 5. |
- Lin, Xiao, et al.
(författare)
-
Novel counter electrode catalysts of niobium oxides supersede Pt for dye-sensitized solar cells
- 2011
-
Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 47:41, s. 11489-11491
-
Tidskriftsartikel (refereegranskat)abstract
- Synthesized niobium oxides (Nb(2)O(5) and NbO(2)) were applied for the first time as counter electrodes (CEs) in dye-sensitized solar cells (DSCs). The DSC using NbO(2) CE showed a higher power conversion efficiency of 7.88%, compared with that of the DSC using Pt CE (7.65%).
|
|
| 6. |
- Shi, Yantao, et al.
(författare)
-
A green route and rational design for ZnO-based high-efficiency photovoltaics
- 2014
-
Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 6:10, s. 5093-5098
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, at room-temperature and without any organic surfactants we reported two green and facile approaches for rapid synthesis of ZnO nanorods (NRs) and nanosheet-based ZnO hierarchical structures (NSHSs). Based on their structural advantages, the quasi-solid ZnO-DSCs achieved a record photoelectric conversion efficiency (PCE) of 6.83%.
|
|
| 7. |
- Shi, Yantao, et al.
(författare)
-
Solid-State Synthesis of ZnO Nanostructures for Quasi-Solid Dye-Sensitized Solar Cells with High Efficiencies up to 6.46%
- 2013
-
Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 25:32, s. 4413-4419
-
Tidskriftsartikel (refereegranskat)abstract
- Solid-state synthesis of ZnO nanostructured building blocks is presented in this work for the fabrication of high efficiency quasi-solid dye-sensitized solar cells (DSSCs). The sponge-like photoanode has high optical density and better connections. Baking the photoanode at low temperature, photoconversion efficiencies of up to 6.46% are yielded by the quasi-solid DSSCs. Furthermore, we demonstrate better stability of our ZnO quasi-solid DSSCs.
|
|
| 8. |
- Shi, Yantao, et al.
(författare)
-
Ultrarapid Sonochemical Synthesis of ZnO Hierarchical Structures : From Fundamental Research to High Efficiencies up to 6.42% for Quasi-Solid Dye-Sensitized Solar Cells
- 2013
-
Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 25:6, s. 1000-1012
-
Tidskriftsartikel (refereegranskat)abstract
- Zinc oxide (ZnO) hierarchical structures (HSs) have recently demonstrated notable photochemical and photovoltaic performances attributed to their nano/micro combined architectures. In this study, ZnO HSs were synthesized at room temperature using ultrarapid sonochemistry. This novel approach can effectively overcome deficiencies in the synthesis via traditional direct precipitation by promoting nucleation and accelerating diffusion. Only 15 min was needed to complete the formation of highly crystallized and uniformed HSs consisting of interconnected monocrystalline nanosheets using sonochemistry. The formation of HSs through in situ observations was interpreted using a new mechanism based on oriented attachment and reconstruction. In the nonequilibrium synthesis system, thicker, porous, and coarse crystallized ZnO sheets were first constructed via oriented attachment of small-sized nanocrystals. After reconstruction, untrathin, integrated, and monocrystalline nanosheets were obtained. According to the two-dimensional nanosheets to three-dimensional HSs, the formation was much more sophisticated because repeated and parallel heterogeneous oriented attachments with reconstructions dominated the final morphologies of the HSs. The relationships between synthetic conditions and HSs structures were established. Based on the photoanodes in dye-sensitized solar cells (DSCs), the performances of these differently structured HSs were tested. HSs with densely assembled nanosheets exhibited better performances in photoelectric conversions. Systematic investigations were also carried out by selecting two representative HSs to demonstrate the critical factors governing the optical and electrical properties of photoanodes. Finally, under AM 1.5 and 100mW cm(-2) light irradiation, high photoelectric conversion efficiencies of up to 6.42% were achieved. These results established a new record for quasi-solid ZnO-based DSCs.
|
|
| 9. |
- Wang, Yudi, et al.
(författare)
-
Optimization of the Performance of Dye-Sensitized Solar Cells Based on Pt-Like TiC Counter Electrodes
- 2012
-
Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :22, s. 3557-3561
-
Tidskriftsartikel (refereegranskat)abstract
- Titanium carbide (TiC) has been used as a counter electrode (CE) catalyst in place of Pt for triiodide reduction in dye-sensitized solar cells (DSCs). Its catalytic activity can be comparable to that of Pt. The effect of the thickness of the TiC layer on the performance of the DSCs was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and Tafel polarization measurements. We found that as the film thickness increased, the fill factor and short-circuit current density increased, which led to improved power-conversion efficiency. When the TiC film was thicker than 20 mu m, however, no significant continuous improvement in the catalytic activity was observed. A high power-conversion efficiency of 6.46?% was obtained for the DSC by using a TiC CE at the optimized film thickness, a value similar to that obtained with a Pt CE.
|
|
| 10. |
- Wang, Yudi, et al.
(författare)
-
Several highly efficient catalysts for Pt-free and FTO-free counter electrodes of dye-sensitized solar cells
- 2012
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 22:9, s. 4009-4014
-
Tidskriftsartikel (refereegranskat)abstract
- Three nanomaterials, namely, titanium carbide (TiC), tungsten oxide (WO2), and vanadium nitride (VN), are introduced into dye-sensitized solar cells (DSCs) as counter electrode (CE) catalysts to replace the expensive Pt CE. Three kinds of substrates of bare glass (BG), Ti foil, and polyimide (PI) film are applied as F-doped tin oxide (FTO)-free substrates for rigid and flexible DSCs; thus realizing FTO-free and Pt-free CEs simultaneously in the DSC system. A carbon layer is used as an electron collector to replace the expensive FTO conductive layer in the insulative BG and PI film. Cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization curves are performed to compare the catalytic activities of these CEs for the reduction of triiodide to iodide. The results demonstrate that the DSCs that use TiC, WO2, and VN as CEs on Ti foil have better photovoltaic performance than those that use CEs on traditional FTO glass. Moreover, the TiC, WO2, and VN on the BG substrates show excellent catalytic activities that can match the performance of the CEs on FTO glasses.
|
|
