Successful preparation of new structure perovskite single crystal X-ray imaging is more sensitive

[ Instrument R&D of Instrument Network ] Perovskite material is currently a semiconductor material that has attracted much attention and has an important position in the research of photovoltaic cells. The basis of the application of perovskite materials in solar cells is the physical and chemical properties such as good light absorption and electrocatalysis brought by its crystal structure. These characteristics not only make perovskite solar cells a hot spot in photovoltaic cell research, but also make perovskite materials one of the breakthrough directions of high-energy radiation detection technologies such as X-rays.

The material used in photovoltaic cell research is a perovskite microcrystalline film, while the X-ray detector uses a large-size perovskite single crystal. Compared with the microcrystalline film, the perovskite single crystal has the characteristics of low defect state, high mobility and more stable, and the preparation cost is also lower, so it has been paid more and more attention in the field of high-energy X-ray detection.

The perovskite single crystal material that has been applied to X-ray detectors has the problems of large dark state current, low signal-to-noise ratio of the device, and severe baseline drift. At present, there have been many research results on perovskite single crystal X-ray detectors trying to solve these problems. For example, the optimized cooling crystallization method was used to prepare two-dimensional perovskite (BDA) PbI4 single crystals, and the cultivation of large-sized Cs3Bi2I9 perovskite single crystals using a low-temperature solution method controlled by nucleation.

Recently, the team of Liu Shengzhong, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, and Dr. Liu Yucheng, Xu Zhuo, and Yang Zhou from Shaanxi Normal University have made new achievements in the field of perovskite single crystal X-ray detectors. Zero-size microstructure non-lead (class) perovskite single crystal high-performance X-ray imaging device. The team adopted a low-temperature solution growth strategy to successfully prepare a large-size zero-dimensional structure bismuth-based perovskite (CH3NH3) 3Bi2I9 (MA3Bi2I9) single crystal.

Experiments have shown that MA3Bi2I9 single crystal not only has high quality and large size, but also solves the problem of preparing perovskite single crystal to replace highly toxic lead element without sacrificing photoelectric performance. On this basis, the design and preparation of integrated X-ray detectors have good working stability and high signal-to-noise ratio, which can achieve highly sensitive and stable X-ray imaging, which helps to promote the application of perovskite materials in X-ray detection. .

As a non-destructive testing method, X-ray imaging is widely used in medical diagnosis, industrial non-destructive testing, security inspection and other fields. However, the core of X-ray imaging-X-ray detectors generally have the problems of high preparation temperature, complex process and high cost, which restricts the further promotion of X-ray imaging. Perovskite single crystal is a better solution to this problem. The research progress of perovskite single crystal not only improves the sensitivity of the X-ray detector, but also reduces the cost and makes an important contribution to the development of the X-ray detector.

Source: Chinese Academy of Sciences