Construction of Hierarchical ZnO Nanowire/Nanosheet Structure for Use in Dye-sensitized Solar Cells

• Main Authors: Wei-TingJiang, 江韋廷
• Other Authors: Jih-Jen Wu
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/73505890236842021457

碩士 === 國立成功大學 === 化學工程學系碩博士班 === 100 === Zinc oxide nanowire/nanosheet hierarchical structure have been successfully synthesized by a wet-chemical route. At first, ZnO nanowire array is synthesized by chemical bath deposition (CBD) on ITO glass substrates. Then, an outer shell composed of many nanosheets structure is grown by another room-temperature CBD on the as-prepared nanowire surface, which becomes a high surface area composite with an excellent electron transport characteristic. High-resolution transmition electron microscopy (HR-TEM) characterizations reveal that the nanowire and nanosheet both are single crystalline with some specific relations between each other. Compared to bare nanowire array, a remarkable increase of the photon to electron efficiency is achieved by using this hierarchical ZnO structure as the photoanode of the dye-sensitized solar cell (DSSC). Using the hierarchical ZnO structure as the photoanode, the DSSC attains a photon to electron efficiency of 5.14% with a composite film thickness of 9 μm. The results of the intensity modulated photocurrent spectroscopy (IMPS) reveal that the hierarchical structures grown by room-temperature CBD possess an excellent electron transport property compared to the as-prepared nanowire. Finally, a wet-chemical route with temperatures below 120 oC is further developed in this study for flexible DSSCs. A photon to electron efficiency of 3.07% is attained by using the low-temperature grown ZnO nanostructure with 3-μm film thickness on ITO glass. So far, the efficiency was below 1% on ITO-PET because of the lack of process optimization.