Solution-processable small molecule based all-organic ultraviolet photodetector

A tetramethoxyfluorene derivative (TMD) based small molecule (C53H54O4) has been used as a donor in a bulk-heterojunction donor-acceptor blend system to realize room temperature solution-processed ultraviolet (UV) photodetector. A systematic opto-electronic study to optimize the weight ratio of the blend of TMD and a common acceptor [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) is presented in this report. The fabricated detector is found to cover the most harmful UVA region while transmitting nearly the entire visible spectrum of light. The responsivity of 6 x 10(-2) A/W, specific detectivity of 9.36 x 10(11)Jones and photosensitivity of 10(5), which are on par with the existing UV photodetectors reported in the literature, are obtained at the wavelength 394 nm under zero bias condition.