Non-radiative recombination losses in polymer light-emitting diodes

► We present a quantitative analysis of the loss of electroluminescence in PLEDs. ► We consider cathode quenching as well as non-radiative trap-assisted recombination. ► Cathode quenching is only significant for devices thinner than 100 nm. ► Non-radiative trap-assisted recombination dominates the efficiency loss up to 45%. ► Reducing the number of traps by one order enhances the efficiency by a factor two.