Improved Hole Interfacial Layer for Planar Perovskite Solar Cells' with Efficiency Exceeding 15%

Planar Structure has been proven to, be efficient and convenient in fabricating low-temperature,and solution-processing perovkite solar Cells (PSCs). Interface control and Crystal film growth of organorrietal halide films are regarded as the most important factors to obtain high-performance PSCs. Herein, we report Solution processed PEDOT:PSS-GeO2 Composite films by simply incorporating the GeO2 aqueous solution into the PEDOT:PSS aqueous dispersion as a hole transport layer in planar PSCs. Besides the merits of high conductivity, ambient stability and interface modification of PEDOT:PSS-GeO2 composite films, the formed island-like GeO2 particles are assumed to act as rowing sites of crystal nucleus of perovskite films during annealing. By the,Seed-mediation of GeO2 particles, a superior CH3NH3PbI3-xClx crystalline filin with large-scale domains and good film uniformity was obtained: The resulting PSC device with PEDOT:PSS-GeO2 composite film as HTL shows a best performance With 15.15% PCE and a fill factor (FF) of 74%. There is a remarkable improvement (similar to 37%) in PCE, from 9.87% to 13.54% (in average for over 120 devices), compared with the reference pristine PEDOT:PSS based device.