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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 (VOC), 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 VOC of 0.498 V, a short‐circuit current (JSC) 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. [ABSTRACT FROM AUTHOR]

The effects of irradiation temperature on helium bubble evolution in UNS N10003 alloys were studied using 500 keV He ion irradiation at a dose of 2 × 1016 ions/cm2 from 650 to 850 °C. As the irradiation temperature increased, the density of the helium bubbles decreased and their size increased. Polyhedral bubbles were observed at 850 °C, and the non-spherical shapes of these bubbles reduced their surface energy. The densities and mean diameters of the bubbles at 650–850 °C show Arrhenius behaviors with activation energies of 1.06 ± 0.17 and 0.35 ± 0.02 eV, respectively. The activation energies indicate that the He bubble evolution at temperatures ranging from 650 to 850 °C is not only controlled by He diffusion via a self-interstitial/He replacement mechanism but is also affected by the migration and coalescence of He clusters or bubbles via surface diffusion. Furthermore, bubble-loop complexes were observed at 750 and 850 °C. With the temperature increasing, the helium bubbles prompted the growth of dislocation loops, suggesting that the interaction between the helium bubbles and the dislocation loops is dependent on the irradiation temperature. [ABSTRACT FROM AUTHOR]

Synergistic effects in the evolution of He bubbles and dislocation loops in Hastelloy N alloy were investigated using transmission electron microscopy and nanoindentation. Results show that the sizes of both He bubbles and dislocation loops induced by the He and Xe irradiation were larger than those in the individual irradiation cases. The corresponding hardening degree of irradiated sample was also measured to be higher than the combined hardening value of two individual irradiation cases. The underlying physics controlling the synergistic effects have revealed that the vacancies are preferentially captured by pre-existed He bubbles as compared to their annihilation with the interstitial atoms during the subsequent Xe irradiation. [ABSTRACT FROM AUTHOR]