The team, led by Professor Su Il In of the Department of Energy Science and Engineering at DGIST, focused on improving the performance of the radiation absorber, which is a key component in betavoltaic batteries that convert beta particles into electricity. Conventional lithium ion batteries face constraints that include finite cycle life, fire risk, and the need for regular recharging and replacement, while existing betavoltaic devices have been limited by low energy conversion efficiency in their absorber materials.
Betavoltaic batteries generate electrical power by converting beta particles, which are high energy electrons emitted during radioactive decay, into electron hole pairs within a semiconductor absorber. Because the radioactive source can have a long half life and the radiation dose can be managed at acceptable levels, such batteries can provide autonomous power over extended periods without any external power supply or maintenance. However, low conversion efficiency and materials challenges have slowed the path to commercialization.
To address these issues, the DGIST led collaboration used carbon 14 nanoparticles as the beta radiation source and introduced a perovskite semiconductor as the radiation absorber layer. The work, carried out in partnership with Professor Jong Hyeok Parks group in the Department of Chemical and Biomolecular Engineering at Yonsei University, applied additive engineering and antisolvent process control to optimize the perovskite film microstructure.
Specifically, the researchers employed methylammonium chloride as an additive in the perovskite fabrication process and used an isopropanol based antisolvent treatment during film formation. This combination proved effective for promoting crystal growth and controlling defects inside the perovskite absorber, leading to larger crystallites and a lower density of internal defects that would otherwise trap charge carriers.
With the improved microstructure, electrons generated by beta particle interactions can travel more freely through the perovskite without undergoing recombination losses. Under these conditions the team experimentally observed an electron avalanche effect, in which a single incident beta particle triggers the generation of approximately 400000 electrons as it propagates through the absorber structure.
The resulting betavoltaic cell reached an energy conversion efficiency of 10.79 percent, which the authors describe as around six times higher than the previously reported best performance of about 1.83 percent for perovskite based betavoltaic batteries. In continuous operation tests exceeding 15 hours, the device maintained stable power output without measurable performance degradation, a result that the team states compares favorably with similar international work reported in Nature in 2024.
According to the researchers, the study is the first to propose and validate a nanoscale design strategy that tightly controls both the material properties and structural features of the radiation absorber to simultaneously boost efficiency, reduce cost, and improve the prospects for commercialization. By demonstrating experimentally that high efficiency betavoltaic batteries are feasible beyond theoretical predictions, the work points toward practical self powered energy sources for use where battery replacement is difficult or impossible.
Potential target applications highlighted by the team include implantable medical electronics that must run for many years, spacecraft and space exploration instruments operating far from maintenance support, and autonomous mobility platforms and AI based systems that benefit from continuous self sufficient power. The reported performance indicates that perovskite betavoltaic cells using carbon 14 sources could become core power units for a range of next generation devices.
"This study is significant in that it has overcome the low efficiency limitations of conventional betavoltaic batteries by utilizing perovskite materials and empirically achieved high efficiency exceeding 10 percent," said Professor Su Il In. "We will continue follow up research to enable commercialization as an independent power source in Fourth Industrial Revolution industries and future AI technology fields that require energy self sufficiency."
The research received support from DGIST general research programs, the Next Generation Isotope Battery Core Materials Technology Advancement Project of the Ministry of Science and ICT, the InnoCORE Project of the four major institutes of science and technology, and the Individual Basic Research Program for mid career researchers of the National Research Foundation of Korea. The findings appear in the international journal Carbon Energy, which focuses on energy and carbon transition topics.
Research Report:Carbon-14 Perovskite Betavoltaics Reach Record 10.79% Efficiency
Related Links
DGIST (Daegu Gyeongbuk Institute of Science and Technology)
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