Boosting hole migration through oxygen species–functionalized graphene interlayer for organic-based optoelectronic devices with enhanced efficiency and long-term durability

Poly(3,4-ethylenedioxythiophene polystyrene sulfonate) (PEDOT:PSS) has attracted attention for use in organic optoelectronic devices because of its efficient hole-migration characteristics, tunable energy, and low cost. However, the acidic and hygroscopic nature of PSS species limit the device performance significantly. Herein we present an efficient approach for improving the hole-transport properties and long-term stability of devices by conformally incorporating O-species functionalized graphene (O-Gr) as hole interfacial layer on the PEDOT:PSS surface. In our density functional theory calculation, the oxygen-containing vacancy in O-Gr can efficiently accept holes and transport them by suppressing the charge recombination. The introduction of O-Gr interlayer promotes efficient charge migration, improves the film properties of the upper layer, and suppresses the leakage current in organic optoelectronic devices, including organic photovoltaics (OPVs) and organic light-emitting diodes (OLEDs). Consequently, an increase of 11% in short-circuit current density (J_sc) is observed in the O-Gr-incorporated OPV in comparing with pristine device. As for the OLEDs, the employ of O-Gr considerably improves the maximum quantum efficiency (27%) and current efficiency (Cd/A) (29%) of device. Tuning hole extraction via the introduction of interfacial O-Gr can be a promising strategy for the advancement of PEDOT:PSS-based organic optoelectronics.