Polyvinylpyrrolidone-enhanced perovskite films for efficient direct X-ray detection

Abstract

In recent years, metal halide perovskites have garnered significant attention in the field of X-ray detection due to their outstanding photoelectric properties, high X-ray attenuation coefficients, and the advantage of being able to be fabricated by low-cost solution processing methods. However, a major challenge in developing perovskite X-ray detectors lies in the low quality of films produced through solution processing. In this work, we introduce an efficient method that employs a straightforward blade-coating technique to successfully prepare MAPbI₃ perovskite films with a thickness of tens of microns under ambient conditions. To further improve the quality of the MAPbI₃ films, we incorporate the polymer polyvinylpyrrolidone (PVP) into the perovskite precursor solution. The addition of PVP promotes crystal growth, resulting in an enlarged grain size and a more uniform arrangement within the perovskite film. This enhancement leads to a reduction in defect density and subsequent improvement in the charge collection efficiency. Consequently, the detector manufactured using the PVP-optimized film exhibits an enhanced X-ray sensitivity of 2.6 × 10³ μC Gy_air⁻¹ cm⁻² and achieves a low detection limit of 11 nGy_air s⁻¹ under 10 keV X-ray energy, surpassing those achieved with the original perovskite film which measured 0.60 × 10³ μC Gy_air⁻¹ cm⁻² and 139 nGy_air s⁻¹ under the same conditions. This work unlocks new prospects for the straightforward and cost-effective manufacture of high-performance X-ray detectors.