Lead-Free 2D Double Perovskite Photodetector Toward Efficient and Stable Self-Powered X-Ray Detection

Lead (Pb)-based halide perovskites have recently made significant breakthroughs in X-ray detection. However, their development is impeded by Pb toxicity. Therefore, developing a green lead-free material for high-energy radiation detection is an imminent task. In this work, an organic molecule, cyclopentylamine (CPA), was successfully integrated into the bismuth-silver bimetallic structure, yielding (CPA) 4 AgBiI 8 . Structurally, this double perovskite possesses remarkable 2D semiconductive characteristics with a bulk resistivity (1.96 × 10 11 Ω cm), obvious spontaneous polarization (0.4 μC cm −2 ), and a superior X-ray absorption coefficient, which endow it with significant potential for efficient self-powered X-ray detection. A gold electrode planar-type photodetector based on the 2D perovskite crystal plane was fabricated through sputtering technology. Specifically, an exceptionally low detection limit of 235 nGy air s −1 was reached by the photodetector, providing exceptional self-powered X-ray photodetection that exceeds the regular needs in medical diagnosis. Besides, the self-powered detector demonstrated a fairly high sensitivity to X-ray detection, measuring 88.8 μC Gy air −1 cm −2 below zero voltage bias. Moreover, the (CPA) 4 AgBiI 8 -based X-ray detector demonstrated excellent enduring stability following a total X-ray irradiation dose of 400.8 mGy and excellent environmental stability. Collectively, these research findings shed light on the design and reconstruction of lead-free halide perovskites toward efficient self-powered X-ray detection.