High Efficiency Formamidinium‐Cesium Perovskite‐Based Radio‐Photovoltaic Cells

Radio‐photovoltaic cell is a micro nuclear battery for devices operating in extreme environments, which converts the decay energy of a radioisotope into electric energy by using a phosphor and a photovoltaic converter. Many phosphors with high light yield and good environmental stability have been developed, but the performance of radio‐photovoltaic cells remains far behind expectations in terms of power density and power conversion efficiency, because of the poor photoelectric conversion efficiency of traditional photovoltaic converters under low‐light conditions. This paper reports an radio‐photovoltaic cell based on an intrinsically stable formamidinium‐cesium perovskite photovoltaic converter exhibiting a wide light wavelength response from 300 to 800 nm, high open‐circuit voltage (V_OC), and remarkable efficiency at low‐light intensity. When a He ions accelerator is adopted as a mimicked α radioisotope source with an equivalent activity of 0.83 mCi cm⁻², the formamidinium‐cesium perovskite radio‐photovoltaic cell achieves a V_OC of 0.498 V, a short‐circuit current (J_SC) of 423.94 nA cm⁻², and a remarkable power conversion efficiency of 0.886%, which is 6.6 times that of the Si reference radio‐photovoltaic cell, as well as the highest among all radio‐photovoltaic cells reported so far. This work provides a theoretical basis for enhancing the performance of radio‐photovoltaic cells.