The performance of OLEDs based on sorbitol doped PEDOT:PSS

We report the performance of OLED devices with a configuration of FTO/sorbitol-PEDOT:PSS (60 nm)/TPD (50 nm)/Alq3 (40 nm)/Al (120 nm) and FTO/plain-PEDOT:PSS (60 nm)/TPD (50 nm)/Alq3 (40 nm)/Al (120 nm) prepared from poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) undoped (plain-PEDOT:PSS) and doped by a constant concentration 5% of sorbitol, respectively. The OLED devices were tested in terms of electrical and optical characteristics in order to investigate the effect of sorbitol doping and thermal annealing on PEDOT:PSS thin film on FTO. The device fabricated from sorbitol-PEDOT:PSS with thermal annealing showed the maximum luminance of 130 (cd m−2). The devices with sorbitol doping showed a lowering of the operating voltage from 6.5 down to 3 V. A constant luminous efficiency higher than 1.8 cd A−1 was obtained in the range of current of 4–7 (mA/cm2) with doped sorbitol.