Efficient energy transfer from blue to red in tetraphenylporphyrin-doped poly(9,9-dioctylfluorene) light-emitting diodes

Abstract

A system of a blue light-emitting host polymer, poly(9,9-dioctylfluorene) (PFO) and a red light-emitting molecular guest molecule, tetraphenylporphyrin (TPP), suitable for use in solution-processable light emitting diodes (LEDs) was developed. The large overlap between the emission from the PFO and the Soret band of the TPP resulted in very efficient Forster transfer. A large Forster transfer radius R0 = 5.4 nm was deduced. Between a TPP weight concentration of 1 and 10%, 95% of the photogenerated excitons were transferred from the PFO to TPP. Finally, in LED devices, external electroluminescence quantum efficiencies of 0.9% at a luminance of 90 cd m-2.