TEMPERATURE-DEPENDENT ELECTRON-HOLE RECOMBINATION IN POLYMER LIGHT-EMITTING-DIODES

The current density-voltage characteristics of poly(dialkoxy p-phenyle ne vinylene) based pol! mer are investigated as a function of temperat ure. Model calculations show that the differences between single and d ouble carrier devices can be well understood by taking into account a bimolecular recombination process. It is found that the bimolecular re combination is terminally activation with an identical activation ener gy as measured for the charge carrier mobility. This demonstrates that the recombination process is of the Langevin type, and explains why t he conversion efficiency (photon/carrier) of a polymer light-emitting diode is temperature independent. (C) 1997 American Institute of Physi cs.