A two-dimensional lead-free double perovskite for self-powered and high performance X-ray detection

Abstract

Two-dimensional Dion–Jacobson (DJ) phase hybrid perovskites are gradually coming to the stage of optoelectronic devices because of their excellent photoelectric properties. These materials exhibit broad application potential in various fields such as solar cells, light-emitting diodes (LEDs), and X-ray detection. Specifically, DJ phase hybrid perovskites are often promising in direct X-ray detection. Herein, a new lead-free DJ-phase layered perovskite, (HA)₂AgBiBr₈ (HA²⁺ = histammonium), single crystal was examined. This newly developed material exhibits excellent semiconductor properties for direct X-ray detection, including high resistivity (8.03 × 10¹⁰ Ω cm), a low trap state density (1.1648 × 10¹¹ cm⁻³), and a large mobility–lifetime value (2.047 × 10⁻³ cm² V⁻¹). Notably, the (HA)₂AgBiBr₈ based X-ray detector performed outstandingly in terms of radiation-to-current response, showing a fast response time (rise time: 21.8 ms, fall time: 42.7 ms). It demonstrated self-powered character, showing a high sensitivity of 252.38 μC Gy_air cm⁻² and low detection limit of 68.9 nGy_air s⁻¹ at 3.10 V mm⁻¹. In addition, the as-fabricated device exhibits excellent imaging performance and long-term stability during X-ray imaging. This work provides a feasible path for the innovative application of organic–inorganic hybrid lead-free perovskites in medical diagnosis and efficient X-ray detection.