Record Stability for Fully Passive Perovskite‐Based X‐Ray Detectors Through the Use of Starch as Templating Agent

High sensitivity and efficient X-ray detectors are needed to promote and boost their application as tools in medical diagnostics and radiotherapy. Lead halide perovskites have emerged recently as a novel class of material for efficient X-ray detection. Although 3D perovskites possess very interesting optoelectronic properties they suffer from low environmental and operational stability. Here a strategy based on using starch as a polymeric template for the fabrication of stable thin film perovskite X-ray detectors is reported. The proposed p-i-n photodiodes can operate with no external bias applied (fully passive devices), reaching a top sensitivity of 5.5 ± 0.2 µC Gy−1 s−1. The device degradation is monitored for samples stored in air for a time window of 630 days, demonstrating exceptional stability: 97% of the initial sensitivity is retained for the best perovskite-starch composite formulation making it the most stable unencapsulated perovskite X-ray detector reported so far.