Gamma‐Ray Radiation Stability of Mixed‐Cation Lead Mixed‐Halide Perovskite Single Crystals

Abstract

Organic–inorganic hybrid lead halide perovskites have shown extraordinary potentials in space photovoltaic technology and high‐energy‐rays detection but their practical application still faces the bottleneck of radiation‐induced instability. Specifically, gamma‐ray radiation hardness is a main concern due to the highest penetrability and difficulty in stopping of gamma‐photons. However, the gamma‐ray radiation stability of perovskites remains controversial. Herein, stability of mixed‐cation lead mixed‐halide FA0.95Cs0.05PbI2.7Br0.3 single crystals under 60Co gamma‐ray radiation of different doses is investigated by tracking the evolution of structural, optical, and photophysical properties. Importantly, they show excellent stability to humidity and heat, eliminating the potential influence of moisture and temperature upon evaluating their gamma‐ray radiation stability. FA0.95Cs0.05PbI2.7Br0.3 single crystals are found stable with an accumulated dose lower than 200 krad and the performance of the irradiated perovskite photodetector could almost completely self‐heal after aging in dark. Perovskite decomposition occurs when the radiation dose is increased to 400 krad or even higher. These phenomena are explained by the synergistic effect between defects generation and lattice reparation caused by ion redistribution during gamma‐ray radiation. These results provide guidance for their practical application in space photovoltaic technology and gamma‐ray detectors.

γ-ray Radiation Hardness of CsPbBr3 Single Crystals and Single-Carrier Devices

“…The XRD result in Figure a shows that the CsPbBr 3 single crystal has excellent phase stability under γ-ray irradiation because no new peaks or peak shifts are observed even in S800. As the chemical changes of the chemical composition in less than 5 wt % will not usually show in the optical and XRD measurements, to further confirm that there are almost undetectable composition changes or decomposition even after a large dose of 800 krad, we characterized samples with different irradiation doses through XPS, which has been confirmed as a useful technique to quantify the elemental ratio and to characterize the chemical environment changes of atoms simultaneously . There is no obvious shift of the binding energy for all irradiated samples, as shown in the Pb 4f XPS spectra in Figure b.…”

“…PL and UV–vis results (Figure c,d) also show that there is almost no discernible change in optical properties for all irradiated samples. These results indicate that different from organic–inorganic hybrid perovskites, which may suffer from phase segregation and degradation after exposure to γ-rays with an accumulated dose larger than 200 krad, all-inorganic CsPbBr 3 perovskite single crystals show outstanding irradiation stability in terms of phase and optical properties under γ-ray irradiation.…”

“…Thus, defect generation and lattice reparation could occur simultaneously or even balance out during irradiation. γ-ray irradiation-induced healing has been observed in organic–inorganic hybrid perovskite polycrystalline films and single crystals, and ion migration caused by γ-rays is considered the main factor at present. , Consequently, the dominance of the lattice reparation process leads to an abnormal performance improvement in S400 in comparison with S0. We conclude that the displacement effect is the main factor responsible for the performance healing in both hole-only and electron-only S400 devices.…”

“…By exploring the phase stability, photophysical properties, trap density, and device performance under different total ionizing doses, and the same total ionizing doses with different transient dose rates, we have investigated the γ-ray radiation hardness of all-inorganic CsPbBr 3 perovskite single crystals and their single-carrier devices. The CsPbBr 3 single crystal itself exhibits excellent irradiation resistance compared to the organic–inorganic hybrid perovskite FA 0.95 Cs 0.05 PbI 2.7 Br 0.3 single crystal, which has a threshold of about 200 krad under γ-ray irradiation …”

“…The CsPbBr 3 single crystal itself exhibits excellent irradiation resistance compared to the organic−inorganic hybrid perovskite FA 0.95 Cs 0.05 PbI 2.7 Br 0.3 single crystal, which has a threshold of about 200 krad under γ-ray irradiation. 39 Ab initio molecular dynamics calculation was performed to further unveil the factors beneficial for the high irradiation tolerance of CsPbBr 3 single crystals. According to traditional irradiation damage mechanisms, irradiation damage is caused by a combination of the ionization effect that generates electron−hole pairs and the displacement effect that gives rise to atoms leaving their initial locations.…”