High response organic ultraviolet photodetectors based on 4,7-diphenyl-1,10-phenanthroline

We demonstrate high response organic ultraviolet photodetectors utilizing 1,3,5-tris(3-methylphenyl-phenylamino)-triphenylamine (m-MTDATA) and 4,7-diphenyl-1,10-phenanthroline (BPhen), which act as electron donor (D) and acceptor (A), respectively. The optimized device exhibits a peak photocurrent of 2.46 mA/cm2 at −12 V under an illumination of 365 nm ultraviolet light irradiation with an intensity of 2.82 mW/cm2, corresponding to a response of 872 mA/W. The high response is attributed to large energy offset, efficient electron transfer from m-MTDATA to BPhen and high charge carrier mobilities of D and A.