High‐Sensitivity Flexible X‐Ray Detectors based on Printed Perovskite Inks

Abstract

The demand for high‐energy radiation detection systems combining high sensitivity, low‐cost and large‐area fabrication has pushed the research on hybrid perovskites as promising materials for X‐ and γ‐photon detection, thanks to their high Z atoms, solution‐processability, and high optoelectronic performance. Here, flexible direct X‐ray detectors are demonstrated with outstanding real‐time detection properties. They are based on printed micrometers‐thick films of methylammonium lead triiodide nanocrystals inks, formulated in low boiling point and benign solvents. Record optoelectronic performances, such as high X‐ray sensitivity (up to 2270 µC Gy−1 cm−2), radiation tolerance over 2.2 Gy of total dose, and fast response time (48 ms) have been achieved by using a simple device architecture and materials processing The functionality under strong bending stress (strain > 10%) and under high X‐ray energy (up to 150 keV) has been assessed, opening the way for flexible real‐time direct radiation detectors and imagers, operating at low‐voltages (bias < 4V) and apt to be fabricated by means of large‐area scalable processes.

Ultra‐Stable and Robust Response to X‐Rays in 2D Layered Perovskite Micro‐Crystalline Films Directly Deposited on Flexible Substrate

“…The latter value is the lowest achieved for perovskite thin film detectors [ 12,13,16,32 ] and is even comparable to the values obtained for high‐quality perovskite single crystals. [ 17,18 ] In fact, to the best of our knowledge, the only superior LoD was found for a 0D perovskite MA 3 Bi 2 I 9 single crystal with a value of 0.62 nGy s −1 . [ 56 ] This excellent LoD is notably permitted by the exceptionally low dark current that grants a signal‐to‐noise‐ratio suitable to detect such a small dose rate (see Figure S8, Supporting Information).…”

“…[ 7–9 ] Their most notable asset is however represented by their good processability, which allows to obtain centimetre‐scale single crystal with trap state densities in the order of 10 9 cm −3 using solution‐based techniques at low temperature (<100 °C). [ 10,11 ] On the one hand HOIPs detectors based on polycrystalline morphologies exhibit fairly good performances, [ 12–17 ] however they are limited by lower bulk resistivity, [ 18 ] higher trap states density, [ 9 ] and significant ion migration effects leading to large dark current drift [ 19 ] with respect to HOIPs detectors based on single crystals. [ 11,20,21 ] Briefly, single crystal‐based devices suffer from the difficulty to produce large‐area pixelated detectors directly integrated onto read‐out electronics, and therefore showing a lack of scalability.…”

Flexible and Wearable Optoelectronic Devices Based on Perovskites

“…In addition to F-PSCs, photodetectors and photomemristors, other perovskite devices have been demonstrated. [105][106][107][108][109] Perovskites are the promising emitters with high color purity and excellent photoluminescence quantum yield. In 2014, Tan et al fabricated perovskite LEDs at room temperature.…”

Fully Textile X‐Ray Detectors Based on Fabric‐Embedded Perovskite Crystals

“…Flexible perovskite-based X-ray detectors have been less explored but, in the last years, the number of reports on their feasibility is rapidly growing. [35][36][37] The possibility of conforming ionizing radiation detectors and dosimeters onto a nonflat object is one of the primary desired features needed, for example, when detectors have to be integrated inside specific probes during radiation therapy, [38] or in easy-wearable objects (e.g., bracelets and belt) and for potential vignetting limitation. Recently, Zhao et al [39] proposed a highly sensitive and flexible direct X-ray detector based on a porous nylon membrane with metal halide perovskite loaded by the infiltration method.…”