We demonstrate highly efficient organic ultraviolet photodetectors using 4,4',4 ''-tris[3-methylpheny(phenyl)amino]triphenylamine (m-MTDATA) and two excellent phosphorescent Cu(I) complexes, [Cu(DPEphos)(DPPz)]BF4 (CuDD) (DPEphos = Bis[2-(diphenylphosphino)phenyl]ether, DPPz = dipyrido(3,2-a:2',3'-c) phenazine) and [Cu(DPEbenz)(DPPz)]BF4 (CuBD) (DPEbenz = 1,2-bis(diphenylphosphino)benzene) to act as the electron donors and acceptors, respectively. The optimized photodetector based on CuDD delivers a photocurrent of 588 mu A/cm(2) at -12 V, corresponding to a response of 560 mA/W under an illumination of 365 nm UV light irradiation with an intensity of 1.05 mW/cm(2) and a detectivity of 2.82 x 10(11) cm Hz(1/2)/W. The high response is attributed to the larger band offset at m-MTDATA/CuDD heterojunction, the suppression of radiative decay of m-MTDATA and efficient electron transfer from m-MTDATA to CuDD. The working mechanism of harvesting high performance is also discussed in detail. (C) 2013 Published by Elsevier Ltd.