Ag@TiO2 Core-Shell type nanocomposites for Dye-sensitized solar cell

• Main Authors: Hsin-Han Hsiao, 蕭新翰
• Other Authors: 張合
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/r6r3hq

碩士 === 國立臺北科技大學 === 機電整合研究所 === 101 === This study employed improved sol-gel method to synthesize nanoparticle of TiO2 and combined it with silver nanometal under low temperature, forming a core-shell nanocomposite which had the nanometal as the core and the TiO2 as the intact coating, in order to explore the effect of synthesis conditions on particle size, structure, and surface characteristics. The material prepared was then packaged to serve as photoanode of the dye-sensitized solar cell, and its application to photoelectric conversion efficiency, UV shielding, and photoelectrochemical reaction were then measured for analysis and discussion.Pure silver nanometal was generated by chemical reduction method, and then its solution was blended with alcoholic solution of alcohol titanium oxide precursor salt to allow TiO2 to coat on surface of the silver nanometal and synthesize Ag@TiO2 core-shell composite. Powder of the Ag@TiO2 core-shell composite was then mixed with Triton X-100 and PEG uniformly and coated on a transparent conductive glass made of fluorine-doped tin oxide conductive substrate (FTO) using a rotary coating machine, so preparation of photoanode of dye-sensitized solar cell was finished. With its structure, silver nanoparticle of Ag@TiO2 core-shell has the characteristic of surface plasma resonance and so can absorb visible light to excite electron-hole. In addition, contact between pure metal and N-shaped TiO2 semiconductor occur the phenomenon of Shottky energy level bend on the interface, so photoelectronic reaction of the cell expands from UV to visible light area. It excites electron-hole pairs to start photoelectrochemical reaction by absorbing only visible light. The intact coating on the surface of silver nanometal effectively protects the interior metal from the corrosion caused by the external the environment. Thus it has the advantage of silver nanometal and the characteristic of TiO2 nano photoelectric material, in which way it prolongs life of the material.Furthermore, this study coated the powder of Ag@TiO2 core-shell composite to FTO conductive glass with a rotary coating machine. After heat treatment at 450℃, the specimen was soaked in dye in light-isolated environment for 24 hours. In subsequent experiment, the result shows thatthe package structure of the dye-sensitized solar cell had photoelectric conversion efficiency up to 3.67%. Besides, when differential proportions of Ag@TiO2 core-shell composite was mixed with Degussa P25 TiO2nanoparticle, the ratio 3:7 generated the best photoelectric conversion efficiency, 5.5%, which further increased film thickness of the photoanode up the optimum 28μm, by 11.2%, generating 6.06% of photoelectric convervision efficiency, an increase of 17% in comparison with mixture of Degussa P25TiO2 nanoparticle.