Preparation Of Two-dimensional Double Perovskite Single Crystals And Study Of Its Performance In X-ray Detection

Since their discovery,perovskites have been considered to have great potential for development.Optoelectronic devices fabricated from perovskites are limited by the instability of perovskites and are easily attacked by water and oxygen.Two-dimensional（2D）perovskites formed by size reduction and introduction of long organic chains endow perovskites with new structures and properties.The excellent stability of 2D perovskites has led people to gradually focus on the research and development of 2D perovskites.As an emerging high-stability semiconductor material,2D perovskites have many applications in optoelectronics.By introducing n-propylamine（PA）long-chain organic cations,2D double perovskite single crystals（PA）₄AgBiBr₈ and（PA）₂CsAgBiBr₇ were prepared by gradient cooling method and constant temperature evaporation method.Such perovskites exhibit suitable band gap and optoelectronic properties.Single crystal still maintains high thermal stability in conventional environment,and has excellent application potential in the field of X-ray detection.The n=1 bulk lead-free 2D double perovskite（PA）₄AgBiBr₈ single crystal was prepared by gradient cooling method.This perovskite single crystal exhibits suitable optical properties,stability,and unique properties for 2D materials.A planar X-ray detector Au/（PA）₄AgBiBr₈/Au was constructed to characterize the properties of（PA）₄AgBiBr₈ single crystal in X-ray detection.At 40 V bias,it has a sensitivity of 6.89μC Gy_air^-1 cm^-2.The isothermal evaporation method is an effective method to prepare（PA）₂CsAgBiBr₇ single crystals,which exhibit a large band gap.The X-ray detector based on（PA）₂CsAgBiBr₇ is vertical,and has shown good performance after photoelectric testing.It has a sensitivity of 178.4μC Gy_air^-1 cm^-2 under X-ray irradiation at 20 V bias.Only the X-ray dose value of 90.47 n Gy/s causes very little harm to the human body when applied in the medical field.Figure 36;Table 9;Reference 111.