Kilogram‐Scale Crystallogenesis of Halide Perovskites for Gamma‐Rays Dose Rate Measurements

Abstract

Gamma‐rays (γ‐rays), wherever present, e.g., in medicine, nuclear environment, or homeland security, due to their strong impact on biological matter, should be closely monitored. There is a need for simple, sensitive γ‐ray detectors at affordable prices. Here, it is shown that γ‐ray detectors based on crystals of methylammonium lead tribromide (MAPbBr3) ideally meet these requirements. Specifically, the γ‐rays incident on a MAPbBr3 crystal generates photocarriers with a high mobility‐lifetime product, allowing radiation detection by photocurrent measurements at room temperatures. Moreover, the MAPbBr3 crystal‐based detectors, equipped with improved carbon electrodes, can operate at low bias (≈1.0 V), hence being suitable for applications in energy‐sparse environments, including space. The γ‐ray detectors reported herein are exposed to radiation from a 60Co source at dose rates up to 2.3 Gy h−1 under ambient conditions for over 100 h, without any sign of degradation. The excellent radiation tolerance stems from the intrinsic structural plasticity of the organic–inorganic halide perovskites, which can be attributed to a defect‐healing process by fast ion migration at the nanoscale level. The sensitivity of the γ‐ray detection upon volume is tested for MAPbBr3 crystals reaching up to 1000 cm3 (3.3 kg in weight) grown by a unique crystal growth technique.

Halide perovskites scintillators: unique promise and current limitations

“…A perovskite-in-polymer membrane system showed negligible current reduction after a total dose of 376.8 Gy (equivalent to 1.88 million chest X-rays) 90 while MAPbBr 3 single crystals irradiated with a 230 Gy dose over 10 hours displayed no losses. 91 The retention of charge transport properties would suggest no significant material degradation, which is promising for scintillators.…”

Hybrid halide perovskite neutron detectors

“…The MAPbBr 3 SCs used in the fabrication of the detector devices were grown using the inverse temperature crystallization method 20 . The SCs of a volume of 2 × 2 × 1 cm 3 were coated by graphite spray on two sides leaving a small gap in-between (6 mm).…”

“…In particular, the chemical formula of MAPbBr 3 contains elements of large atomic weight (high-Z), such as Pb and Br, thus leading to a high material density (~ 4 g cm −3 ), which is necessary for efficient impact ionization. Moreover, it has been shown that high-quality large MAPbBr 3 crystals, weighting even more than one kilogram, can be grown 20 . Such crystals are characterized by a unique correlation of relatively low trap concentration and high resistivity.…”

“…Numerous literature reports documented alpha- 21 , beta-particles 22 , X-ray 10 , 12 – 15 , 23 – 27 and γ-ray 11 , 16 – 20 , 28 – 31 detection by perovskite-based devices. All of them revealed exceptional performance, being capable of detecting a wide range of radiation energies and dose-rates, with sensitivities often equal or even better than the best-in-class semiconducting materials 32 .…”

“…Furthermore, the long-term operational stability, i.e., radiation damage of the perovskite material, was tested under neutron irradiation. Since the neutron detectors, based on high-quality MAPbBr 3 SCs manufactured by us, showed the best properties 20 , all the results presented hereinafter will concern the devices designed around MAPbBr 3 SCs equipped with graphite spray (Fig. 1 b) or carbon epoxy electrodes.…”