Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Improved conversion efficiency of Ag2S quantum dot-sensitized solar cells based on TiO2 nanotubes with a ZnO recombination barrier layer | Chen et al. Nanoscale Research Letters 2011 6 462 http content 6 1 462 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Improved conversion efficiency of Ag2S quantum dot-sensitized solar cells based on TiO2 nanotubes with a ZnO recombination barrier layer Chong Chen1 Yi Xie1 Ghafar Ali1 2 Seung Hwa Yoo1 and Sung Oh Cho1 Abstract We improve the conversion efficiency of Ag2S quantum dot QD -sensitized TiO2 nanotube-array electrodes by chemically depositing ZnO recombination barrier layer on plain TiO2 nanotube-array electrodes. The optical properties structural properties compositional analysis and photoelectrochemistry properties of prepared electrodes have been investigated. It is found that for the prepared electrodes with increasing the cycles of Ag2S deposition the photocurrent density and the conversion efficiency increase. In addition as compared to the Ag2S QD-sensitized TiO2 nanotube-array electrode without the ZnO layers the conversion efficiency of the electrode with the ZnO layers increases significantly due to the formation of efficient recombination layer between the TiO2 nanotube array and electrolyte. Keywords quantum dots TiO2 nanotube Ag2S solar cells Introduction In recent years dye-sensitized solar cells DSSCs have attracted much attention as a promising alternative to conventional p-n junction photovoltaic devices because of their low cost and ease of production 1-4 . A high power conversion efficiency of was achieved 5 . The conventional DSSCs consist of dye-sensitized nanocrystalline TiO2 film as working electrode electrolyte and opposite electrode. In DSSCs the organic dyes act as light absorbers and usually have a strong absorption band in the visible. Various organic dyes such as N719 and black dye have been applied for improving the efficiency light absorption coverage stability and reducing the cost. However the organic dyes have a weak absorbance at shorter wavelengths. Materials
