High-Performance Perovskite Betavoltaics Employing High-Crystallinity MAPbBr Films.

Long-life and self-powered betavoltaic batteries are extremely attractive for many fields that require a long-term power supply, such as space exploration, polar exploration, and implantable medical technology. Organic lead halide perovskites are great potential candidate materials for betavoltaic batteries due to the large attenuation coefficient and the long carrier diffusion length, which guarantee the scale match between the penetration depth of β particles and the carrier diffusion length. However, the performance of perovskite betavoltaics is limited by the fabrication process of the thick and high-crystallinity perovskite film. In this work, we demonstrated high-performance perovskite betavoltaic cells using thick, high-quality, and wide-band-gap MAPbBr polycrystalline films. The solvent annealing method was adopted to improve the crystallinity and eliminate the pinholes in the MAPbBr film. The optimal MAPbBr betavoltaic cell achieved a power conversion efficiency (PCE) of 5.35% and a maximum output power of 1.203 μW under radiation of electrons of 15 keV with an equivalent activity of 253 mCi. These results are a nearly 50% improvement from previous reports. Effects of the MAPbBr perovskite layer thickness on the device performance were also discussed. The mechanisms of film-growth processes and device physics could provide insights for the research community of perovskites and betavoltaics.