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Li Y.,Xian Jiaotong University | He X.-L.,Jiangxi Province Key Laboratory of Precision Drive and Control | Lian C.-X.,Xian Jiaotong University | Yao H.-L.,Xian Jiaotong University | And 4 more authors.
ACS Sustainable Chemistry and Engineering | Year: 2016

For the fabrication of highly efficient all-solid-state dye-sensitized solar cells, a full coverage of electrolyte on dye/TiO2 surface and a continuous electrolyte route from dye/TiO2 surface to counter electrode are the most important issues, which depend heavily on the infiltration and precipitation behavior of solid electrolyte into porous photoanode. In this paper, an important experimental strategy, fast evaporation of the solvent at 80 °C under a low pressure, was explored for the first time to create in situ continuous charge transfer pathways after the infiltration of polymer electrolyte solution into a dual-porous TiO2 film created by vacuum cold spraying. It was found that with the novel strategy very good electrolyte coverage could be realized on the dye/TiO2 surface, and continuous electrolyte fibers could be developed in the sub-micro-pores of the dual-porous TiO2 film, which could serve as a highway for fast electron transport between counter electrode and photoanode. As a result, a very high photo-to-electric energy conversion efficiency was demonstrated by the solvent-free polymer electrolyte solar cell. © 2016 American Chemical Society. Source

Li Y.,Xian Jiaotong University | He X.-L.,Jiangxi Province Key Laboratory of Precision Drive and Control | Ding B.,Xian Jiaotong University | Gao L.-L.,Xian Jiaotong University | And 3 more authors.
Journal of Power Sources | Year: 2016

The full coverage of the perovskite film on the substrate surface is of significant importance for the high performance perovskite solar cells. In order to obtain full coverage perovskite films by one-step deposition method, the microstructures of both uncovered areas and covered areas of the CH3NH3PbI3 film are comparatively investigated. Results show that the uncovered area indeed has an ultra-thin layer of CH3NH3PbI3 film which is too thin to cover the rough surface morphology of the substrate, and the localized solute accumulation due to long crystal growth time is responsible for the non-full coverage of the perovskite film. Then by decreasing the crystal growth time, the localized solute accumulation is eliminated gradually and subsequently a full coverage of perovskite film on substrate surface is realized. As a result, the perovskite solar cells show a conversion efficiency of ∼13% with the uniform and full coverage perovskite film. © 2016 Elsevier B.V. All rights reserved. Source

He X.-L.,Xian Jiaotong University | He X.-L.,Jiangxi Province Key Laboratory of Precision Drive and Control | Shen R.-X.,Xian Jiaotong University | Yang G.-J.,Xian Jiaotong University | And 2 more authors.
RSC Advances | Year: 2015

The electrocatalytic behavior of flexible platinum (Pt) counter electrodes (CEs) is of great importance to practical applications of flexible dye-sensitized solar cells (DSCs). In this study, the electrocatalytic activity of two different flexible Pt CEs with continuous and non-continuous Pt films, which were prepared by a sputtering method and an electroless deposition method, respectively, was studied under alternative bending conditions. The data obtained from electrochemical impedance spectroscopy measurements show that the electrocatalytic activity of the continuous Pt CEs slightly increases with the increasing bending cycles, due to the enhanced bare surface area formed from localized delamination and cracking. In contrast, the non-continuous Pt CEs demonstrate much higher resistance towards bending tests, i.e., their electrocatalytic activity remains unchanged even after 25 000 bending cycles. This can be attributed to the high strain tolerance and unique surface structure for this kind of non-continuous Pt CE, which helps the release of stress during the bending tests. This journal is © The Royal Society of Chemistry. Source

Chen Z.,Jiangxi Province Key Laboratory of Precision Drive and Control | Chen Z.,Nanchang Institute of Technology | Zhang J.H.,Nanchang Institute of Technology | Chen S.,Huazhong University of Science and Technology | And 7 more authors.
Journal of Alloys and Compounds | Year: 2015

By utilizing a versatile solution combustion synthesis (SCS) method, pure and well-crystallized Sr2MgSiO5:Eu2+, Mn2+ phosphors for white LED were successfully prepared. The results show that the obtained Sr2MgSiO5:Eu2+, Mn2+ phosphors have good crystallinity, and strong emission under near-ultraviolet (NUV) light excitation, which emits tri-band colors (blue, green, and red, RGB) peaking at 462, 535, and 668 nm, respectively. The emission spectrum with the peak at 462, 535 nm corresponds to the transition from the 4f65d excited state to the 4f7 ground state of Eu2+ ion, and the red emission band of 668 nm is attributed to 4T → 6A transition of 3d5 level of Mn2+ ions. It is suggested that the as-prepared nanostructure Sr2MgSiO5:Eu2+, Mn2+ samples as a single-host full-color phosphor have high potential for phosphor-converted white LEDs application. © 2015 Elsevier B.V. Source

He X.-L.,Jiangxi Province Key Laboratory of Precision Drive and Control | Yang G.-J.,Xian Jiaotong University | Li C.-J.,Xian Jiaotong University | Liu M.,Xian Jiaotong University | Fan S.-Q.,University of Queensland
Journal of Power Sources | Year: 2015

(Graph Presented). Flexibility, as well as efficiency, of flexible dye-sensitized solar cells (DSCs) is of significant importance to their applications. In this study, quantitative bending test, carried out with a lab-developed solar cell bending tester, is used to simulate the flexible service condition. The photovoltaic performance, morphology of the photoanode and electrochemical property evolution during bending service are examined to aim at understanding the bending failure mechanism for the flexible DSCs under repeated outward bending (the TiO2 film in the photoanode is in tension). Results show that when the bending radius is 12 mm, the efficiency of the plastic DSCs keeps unchanged with increasing the bending cycle. When the bending radius is smaller than 12 mm, the efficiency of the flexible DSCs decreases with increasing the bending cycle. The electrochemical impedance spectroscopy results show that the increase of the electron transport resistance (Rt) in TiO2 network is responsible for the degradation of efficiency. Furthermore, the photoanodes after repeated bending is cracking and spalling off from the ITO surface. Finally, a failure model for the flexible DSCs under repeated outward bending is proposed. © 2015 Elsevier B.V. All rights reserved. Source

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