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Hybrid halide perovskites are a new class of solution-processed semiconductors that combine low-temperature (<100 °C) synthesis, high charge carrier diffusion length and low defect density. The past few years, hybrid halide perovskites such as $CH_{3}NH_{3}PbI_{3}$ have shown promising results for the detection of high-energy ionizing radiation (X- and Gamma-rays).[1] Their large-scale commercialization is however hindered by their poor stability, owing to the volatility of the small organic cation $CH_{3}NH_{3}^{+}$.
2D layered hybrid halide perovskites $(R-NH_{3})_{2}PbX_{4}$ (R = organic chain, X = $Cl^{-}$, $Br^{-}$, $I^{-}$) have recently shown an increasing interest in the fields of solar cells and LEDs. This sub-class of perovskite crystallizes in a natural, self-assembled quantum well structure and possess several interesting features, among which a much better stability than their 3D counterparts.[2,3] We will present in this work the first solid-state ionizing radiation detector based on a 2D layered hybrid perovskite. This material can be deposited from solution in the form of micro-crystalline thin films that display a single crystalline orientation. We will expose the direct integration of this material onto a pre-patterned flexible substrate and demonstrate the effective detection of X-Rays with sensitivity values as high as 757 uC.Gy-1.cm-2 and a Limit of Detection (LoD) of 8 nGy.s-1, which is among the lowest reported value for solid-state detectors. 2D perovskites offers the prospects of flexible solid-state detectors capable of working at low radiation flux for real-time X-Ray dosimetry.
[1] L. Basiricò, S. P. Senanayak, A. Ciavatti, M. Abdi-Jalebi, B. Fraboni and H. Sirringhaus, Adv. Funct. Mater., 2019, 9.
[2] D. B. Mitzi, Journal of the Chemical Society, Dalton Transactions, 2001, 0, 1–12.
[3] J. V. Passarelli, D. J. Fairfield, N. A. Sather, M. P. Hendricks, H. Sai, C. L. Stern and S. I. Stupp, J. Am. Chem. Soc., 2018, 140, 7313–7323.
Figure caption. (a) Schematic of the device structure. Bottom: graphical representation of the $(R-NH_{3})_{2}PbX_{4}$ crystal structure projected along the direction <010> showing the stacking of the 2D layers. (b) Photograph (left) and microscope image (right) showing the crystal grains morphology close to the pixel area.
