Performance enhancement of all-inorganic carbon-based CsPbI2Br solar cells by using silane modification

The CsPbI2Br perovskite solar cells (PSCs) based on the carbon electrodes are considered as promising photovoltaic devices with low cost and excellent thermal stability. Although the power conversion efficiency (PCE) has made remarkable progress, recombination originating from surface defect states of perovskite is still serious. In this work, CsPbI2Br layer was treated by n-propyltrimethoxysilane (NPTMS) before covering carbon electrode, and effects of NPTMS modification on the microstructure and optoelectronic properties of CsPbI2Br films were systematically studied. We found that NPTMS effectively passivated the CsPbI2Br surface states and inhibited nonradiative recombination via the strong coordination of O atom with the surface atoms. As a result, the power conversion efficiency of the CsPbI2Br perovskite solar cell increased from 8.78 to 10.22%.