Efficient organic light-emitting diodes through up-conversion from triplet to singlet excited states of exciplexes

Enhanced electroluminescence efficiency is achieved in organic light-emitting diodes through delayed fluorescence of the exciplex state formed between 4,40,4 ''-tris[3-methylphenyl(phenyl) amino]triphenylamine (m-MTDATA) as an electron-donating material and 2,8-bis(diphenylphosphoryl) dibenzo[b,d]thiophene (PPT) as an electron-accepting material. The devices exhibited maximum external electroluminescence quantum and power efficiencies of 10.0% and 47.0 lm/W, respectively. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4737006]