The application of organic electronic materials for the detection of ionizing radiations is very\nappealing thanks to their mechanical flexibility, low-cost and simple processing in comparison\nto their inorganic counterpart. In this work we investigate the direct X-ray photoconversion\nprocess in organic thin film photoconductors. The devices are realized by drop casting\nsolution-processed bis-(triisopropylsilylethynyl)pentacene (TIPS-pentacene) onto flexible\nplastic substrates patterned with metal electrodes; they exhibit a strong sensitivity to X-rays\ndespite the low X-ray photon absorption typical of low-Z organic materials. We propose a\nmodel, based on the accumulation of photogenerated charges and photoconductive gain, able\nto describe the magnitude as well as the dynamics of the X-ray-induced photocurrent.\nThis finding allows us to fabricate and test a flexible 22 pixelated X-ray detector operating\nat 0.2V, with gain and sensitivity up to 4.7104 and 77,000 nC mGy1 cm3, respectively.
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