Nanotechnology has emerged as a key driver in radioisotope batteries, which offer unique advantages for long-term, maintenance-free energy supply in deep space exploration, medical implants, and nuclear waste utilization. This review summarizes recent progress in applying nanomaterials and nanostructures to overcome the limitations of nuclear batteries, including low energy conversion efficiency and poor stability. The main content focuses on the three primary conversion mechanisms of thermoelectric, radio-voltaic, and radio-photovoltaic batteries, discussing high-performance thermoelectric nanomaterials such as SiGe alloys, wide-bandgap semiconductors including diamond and SiC for enhanced carrier collection, and nanoscale radionuclide ources to mitigate self-absorption losses. This review further elaborates on how nanostructure regulation and interface engineering have significantly improved carrier collection efficiency and device stability. These advances have enabled notable civilian applications, such as the BV100 and “Zhulong No.1” nuclear batteries. Despite this progress, challenges remain in ensuring long-term material stability under extreme environments, maintaining performance consistency during macroscopic device integration, and addressing the high fabrication costs. The review concludes by outlining future research directions, including the development of novel nanomaterial systems, innovative nanostructure designs, scalable manufacturing processes, and enhanced device stability and safety, to further advance next-generation radioisotope batteries.

Organic radiophotovoltaic (ORPV) systems have attracted increasing interest for long-lifetime energy harvesting under weak radiative environments. In this work, ternary organic photovoltaic devices driven by 3H/ZnS:Cu radioluminescence were theoretically investigated using density functional theory/time-dependent density functional theory calculations and SCAPS-1D simulations. The electronic structures, absorption characteristics, exciton dissociation behavior, carrier transport properties, and device performance of P3HT, PM6, and ICBA systems were systematically analyzed. The results suggest that introducing PM6 into the P3HT:ICBA system may improve carrier transport balance, optimize energy-level alignment, and enhance photon utilization under narrow-spectrum radioluminescent excitation. Simulated ternary devices exhibit improved fill factor and power conversion efficiency (PCE) compared with binary devices under both AM1.5G sunlight and 3H/ZnS:Cu tritium light conditions. Under tritium light, the FF increases from 52.11% to 54.71%, while the maximum PCE improves from 10.66% to 11.33%. However, the enhanced PCE under tritium light should be interpreted cautiously, as it mainly arises from normalization under extremely low incident light intensity, while the corresponding absolute output power remains on the order of ∼10−5 mW/cm2. In addition, a flexible cylindrical ORPV architecture compatible with roll-to-roll processing was conceptually proposed, and the effects of phosphor degradation, radiation-induced aging, and long-term operational stability were qualitatively discussed. Although the present work is entirely simulation-based and still requires experimental validation, it provides theoretical insight into material selection and structural optimization for future ultra-low-power microelectromechanical systems and self-powered sensing applications.