Flexible\nInkjet-Printed Triple Cation Perovskite X‑ray Detectors

Abstract

Flexible\ndirect conversion X-ray detectors enable a variety of novel applications\nin medicine, industry, and science. Hybrid organic–inorganic\nperovskite semiconductors containing elements of high atomic number\ncombine an efficient X-ray absorption with excellent charge transport\nproperties. Due to their additional cost-effective and low-temperature\nprocessability, perovskite semiconductors represent promising candidates\nto be used as active materials in flexible X-ray detectors. Inspired\nby the promising results recently reported on X-ray detectors that\nare based on either triple cation perovskites or inkjet-printed perovskite\nquantum dots, we here investigate flexible inkjet-printed triple cation\nperovskite X-ray detectors. The performance of the detectors is evaluated\nby the X-ray sensitivity, the dark current, and the X-ray stability.\nExposed to 70 kVp X-ray radiation, reproducible and highly competitive\nX-ray sensitivities of up to 59.9 μC/(Gy_aircm²) at low operating voltages of 0.1 V are achieved. Furthermore,\na significant dark current reduction is demonstrated in our detectors\nby replacing spin-coated poly­(3,4-ethylenedioxythiophene)/poly­(styrenesulfonate)\n(PEDOT:PSS) with sputtered NiO_<i>x</i> hole transport\nlayers. Finally, stable operation of a flexible X-ray detector for\na cumulative X-ray exposure of 4 Gy_air is presented, and\nthe applicability of our devices as X-ray imaging detectors is shown.\nThe results of this study represent a proof of concept toward flexible\ndirect conversion X-ray detectors realized by cost-effective and high-throughput\ndigital inkjet printing.