Chromium oxide decorated on carbon materials to tune the electron transport layer (ETL) of perovskite solar cells and X-ray detectors

Abstract

Perovskites hold great promise for the fabrication of solar cells with high efficiency and low costs. Power conversion efficiencies (PCEs) have increased dramatically, highlighting the remarkable potential of perovskite materials. It has been found that charge transport layers are crucial for the functionality and durability of devices. Particularly in perovskite solar cells (PSCs), charge extraction at the interface is not particularly effective when using a conventional PCBM as an electron transport layer (ETL). Cr2O3 exhibits better stability under UV exposure and better band alignment with the perovskite layer, which is beneficial for electron extraction. However, the low conductivity and mobility of Cr2O3 can be improved by fabricating hybrid composites with graphitic particles (GPs) and carbon nanotubes (CNTs). Hybrid ETLs with Cr2O3@GP and Cr2O3@CNT exhibited improved PCE of 18.5% and 26.8% as compared to plane ETL. When Cr2O3@GP/CNT was added to the ETL, the ETL conductivity significantly improved, and the series resistance declined. In addition, after a 336-hour stability measurement, the hybrid ETL still had almost 96% of its initial PCE. Moreover, the X-ray detector's sensitivity increased by 24.7% and 28.1%, for Cr2O3@GP and Cr2O3@CNT, respectively. These findings provide a path for commercializing PSCs and X-ray detectors by presenting a feasible method to significantly improve their stability and performance.