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

•Cr2O3@GPs/CNTs nanocomposite was fabricated to tune the electron transport layer of solar cells and X-ray detectors.•Hybrid ETLs with Cr2O3@GP and Cr2O3@CNT exhibited improved PCE of 18.5% and 26.8%.•The ETL conductivity significantly improved, and the series resistance declined.•After 336-hour stability measurement, the hybrid ETL still had almost 96% of its initial PCE.•The X-ray detector's sensitivity increased by 24.7% and 28.1%, for Cr2O3@GP and Cr2O3@CNT, respectively.