Tritiated Perovskites: Experimental Insights for Tritium Betavoltaic Batteries

A new approach to developing an intrinsic betavoltaic battery is demonstrated by incorporating radiation-emitting isotopes, such as tritium, directly into the perovskite materials enabling direct power harvesting. The estimated power density for tritiated perovskite is 33.15 mW g-1 compared to 3.25 mW g-1 with conventional planar source-device structure. The long-term energy release is predicted at 73.8 kWh/kg of tritiated methylammonium lead triiodide (tritiated MAPbI3 or CT3NT3PbI3) over 12.32 years. A CT3NT3PbI3 crystal was synthesized using 4.44 mCi of tritiated water. Tritium incorporation into the final perovskite device was confirmed, with an uptake ratio of ( $2.1~\pm ~0.2$ )% from tritiated water to methylammonium iodide (MAI) precursor. However, the fabricated devices did not exhibit rectifying behavior, possibly due to the unpolished surface. The I–V curve also exhibited significant hysteresis. A key challenge identified for increasing the tritium uptake ratio is to develop a high concentration of tritiated water.