Modification Of TiO₂ Nanoparticle Photoanode And Performance Research Of The Sensitized Solar Cell

TiO2 nanoparticle has been commonly used as photoanode in conventional Dye Sensitized Solar Cells(DSSCs) and inorganic semiconductor sensitized solar cell, previous research has demonstrated that the enhancement of cell efficiency can be substantially promoted by modification of TiO2 photoanode. In the thesis, based on the optimized preparation of DSSC and Cu2ZnSnS4(CZTS) sensitized solar cell, TiO2 photoanodes were decorated with varied approaches and their impact upon device performance was investigated.Firstly, TiO2 nanoparticle photoanode based DSSC was optimized fabricated. Being treated with TiO2 nanowire, TiO2 hollow sphere and graphene oxide(GO), the effect on optoelectronic properties of DSSC was systematically studied. It was revealed that the cell efficiency could be improved via these ways, besides, the highest power conversion efficiency was achieved while GO was utilized.Secondly, CZTS was adopted to replace conventional dye in DSSC and then CZTS sensitized solar cell was constructed across self-assemble technique. The influence on the cell device induced by the decoration with different materials was explored, including MPA(Mercaptopropionic acid), HrGO(Hydrazine hydrate reduced graphene oxide) and TrGO(Thiol reduced graphene oxide). The results showed that TrGO functioned a lot to improve the photovoltaic property of solar cell. It acted not only to creat more electrons through its thiol groups to attach CZTS, but to offer fast pathway for electron transport, reducing charge recombination rate, thus the chief efficiency was given in the case of TrGO.Finally, TiO2-TrGO-CZTS composite structure was synthesized using in-situ growth method with TiO2-TrGO being substrate. The research of its photoelectric performance was then conducted by changing synthesized condition, incorporating solvent, sulfur source and reaction time. It could be found that the presence of TrGO would facilitate the nucleation and growth of CZTS by providing nucleation site in production process, for which the CZTS was obtained with smaller size and larger distribution. It can also be inferred that the surafece tension of solvent disparately affected the growth state of CZTS, the highest loading amount was attained when ethanol with minimum tension was choosen, next was DMF, water ranked last and impurity CuS appeared in the case. Another impurity SnS can be observed when sulfur powder was selected as sulfur source. Moreover, short reaction time may lead to the generation of CuS, extending reaction duration was favorable to get pure TiO2-TrGO-CZTS composite structure. Under the condtion of 24 h, the composite electrode and its deveice exhibited best photoelectrical performance. As reaction time proceeded to 48 h, TiO2-TrGO-CZTS structure began to fall off FTO glass, the performance decreased instead.