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Description
Hybrid halide perovskites have recently emerged as highly promising materials for radiation detection, enabling efficient sensing of a broad spectrum of radiation, from UV–visible photons to high-energy X-rays, γ-rays, and charged particle beams. Significant advances in device engineering and material optimization have led to remarkable performance in terms of sensitivity and charge collection efficiency. However, despite these achievements, a comprehensive understanding of the fundamental detection mechanisms and their impact on device behavior under realistic operating conditions remains incomplete. In particular, the dependence of the detector response on the dose rate, although frequently observed, has been largely overlooked and is often not considered a limiting factor.
In this work, we investigate the dose-rate dependence of hybrid perovskite-based radiation detectors and demonstrate its critical impact on their performance as dosimeters and beam monitors. Using a flexible 2D perovskite (PEA₂PbBr₄) thin-film photoconductor as a model system, we systematically analyze the detector response under different irradiation modalities, including UV light, X-rays, γ-rays, and proton beams. While the collected charge is found to scale linearly with the total delivered dose, the photocurrent exhibits a pronounced sublinear dependence on the dose rate or photon flux across all investigated radiation sources. This universal behavior highlights a common underlying physical mechanism governing the detection process.
We show that such dose-rate dependence leads to significant distortions in practical applications. In clinically relevant scenarios, including external beam radiotherapy and brachytherapy, the non-linear response results in misestimation of dose distributions, affecting both transversal beam profiling and depth-dose reconstruction. In proton therapy conditions, this manifests as deformation of the beam tails and underestimation of the Bragg peak amplitude, while in γ-ray brachytherapy it leads to systematic deviations in percentage depth dose measurements. These effects are particularly critical given that medical dosimetry requires a flat and dose-rate-independent response to ensure accurate and reliable dose assessment.
To elucidate the origin of this behavior, we develop a physical model based on trap-assisted carrier dynamics in the perovskite active layer. The model accounts for the interplay between carrier trapping, emission, and recombination processes, and introduces the injected charge density (ICD) as a unifying parameter to describe different irradiation conditions. By considering two distinct trap distributions with different activation energies, the model successfully reproduces both the steady-state sublinear response and the temporal evolution of the photocurrent under varying irradiation regimes. The analysis reveals that deep trap states dominate the response at low ICD, enhancing photoconductive gain, while shallower traps become active at higher injection levels, leading to gain compression.
Finally, we propose and experimentally validate a calibration methodology that corrects for the dose-rate-induced distortions, allowing an accurate reconstruction of proton beam profiles in agreement with reference dosimeters.
Overall, this work provides a comprehensive framework for understanding and mitigating dose-rate effects in perovskite radiation detectors, highlighting both a fundamental limitation and a pathway toward their reliable implementation in real-world dosimetric applications.
L. Basirico’ et al, under revision, 2026