Realization of high detectivity organic ultraviolet photodetectors by modifying polymer active layer

Organic ultraviolet photodetectors (UV-PDs) consisting of a polymer active layer of poly (N-vinyl carbazole):[6,6]-phenyl-C71-butyric acid methyl ester were fabricated, and the properties of UV-PDs were systematically investigated by optimizing the thickness of active layer and temperature of thermal annealing. The result showed that, under an illumination of 350 nm ultraviolet light with an intensity of 0.6 mW/cm(2), the device exhibited a high detectivity of 1.07 x 10(12) Jones, which is among the highest detectivity of the reported inverted UV-PDs. Through the UV-Vis absorption spectra and atomic force microscopy measurement, along with charge carrier mobility analysis, the high performance of UV-PDs was attributed to the improved UV absorption, preferred morphology and effective charge transport of polymer active layer. (C) 2014 Elsevier B.V. All rights reserved.