石墨烯修饰TiO2-SnO2混杂光阳极的分子层面结构设计及制备研究

基于分子层面对材料进行设计，首次采用单源前驱体制备石墨烯修饰TiO2-SnO2混杂光阳极，材料有望具有高比表面积、结构均匀以及电子快速传输等特性，提升钙钛矿太阳能电池的效率及稳定性。利用配体中有机官能团络合获得的单源前驱体，可以调整钛醇盐与锡前驱体的水解速度，有效避免溶胶-凝胶法制备中因水解速度不同而造成的分相问题。所制备TiO2-SnO2混杂光阳极的组分比例可以根据所采用的单源前驱体结构进行调整，并通过引入均匀分散的石墨烯，通过其片状结构的相互搭错形成电子快速传输通道，提高光生电子分离速度。采用单源前驱体所制备的石墨烯修饰TiO2-SnO2混杂光阳极在钙钛矿太阳能电池中应用时，其均相结构不仅能降低由于SnO2较低导带边缘和低电流整流特性带来的SnO2-钙钛矿界面的高电子复合，还能减少TiO2表面OH对CH3NH3PbI3有机物的破坏，为制备高转换效率且性能稳定的钙钛矿太阳能电池提供基础。

A kind of photoanode with graphene doped TiO2-SnO2 hybrid structure, which is prepared by using single source precursor (SSP), is promising to have a variety of excellent properties to improve the efficiency and stability of perovskite solar cells, such as high surface area, homogenous structure, fast electronic transfer channel, et al. The SSPs, synthesized by coordination of organic ligands with functional group to metallic precursors, are very efficient for avoiding phase separation by adjusting the hydrolysis rate of titanium alkoxides Ti(OR)4 and the Sn precursor. The component ratio of TiO2-SnO2 hybrid photoanode could be controlled by using SSPs with different structures. Furthermore, graphene are introduced into the TiO2-SnO2 hybrid photoanode to improve the electron separation and transfer speed. As the graphene is of sheet structure, they can connect with each other when graphene is in a suitable concentration, forming a fast path for electron transfer. The graphene doped TiO2-SnO2 hybrid photoanode (prepared by SSP) has several unique advantages for perovskite solar cells, the homogeneous TiO2-SnO2 structure can not only depress the severe charge recombination between SnO2 and perovskite caused by the inherent lower conduction band edge and low current rectification property of SnO2, and can also reduce the decomposition of CH3NH3PbI3 caused by the OH on the TiO2 surface. This research can provide both theoretical and experimental foundation for the fabrication of perovskite solar cells with high efficiency and long stability.