Tuning of electron transport layers using MXene/metal-oxide nanocomposites for perovskite solar cells and X-ray detectors

This work elaborates on the decoration of metal oxides (ZnO and Fe₃O₄) between MXene sheets for use as the supporting geometry of PCBM electron transport layers (ETLs) in perovskite solar cells and X-ray detectors. The metal oxide supports for carrying the plentiful charge carriers and the hydrophobic nature of MXenes provide an easy charge transfer path through their flakes and a smooth surface for the ETL. The developed interface engineering based on the MXene/ZnO and MXene/Fe₃O₄ hybrid ETL results in improved power conversion efficiencies (PCEs) of 13.31% and 13.79%, respectively. The observed PCE is improved to 25.80% and 30.34% by blending the MXene/ZnO and MXene/Fe₃O₄ nanoparticles with the PCBM layer, respectively. Various factors, such as surface modification, swift interfacial interaction, roughness decrement, and charge transport improvement, are strongly influenced to improve the device performance. Moreover, X-ray detectors with the MXene/Fe₃O₄-modulated PCBM ETL achieve a CCD-DCD, sensitivity, mobility, and trap density of 15.46 μA cm⁻², 4.63 mA per Gy per cm², 5.21 × 10⁻⁴ cm² V⁻¹ s⁻¹, and 1.47 × 10¹⁵ cm² V⁻¹ s⁻¹, respectively. Metal oxide-decorated MXene sheets incorporating the PCBM ETL are a significant route for improving the photoactive species generation, long-term stability, and high mobility of perovskite-based devices.