Energy level engineering of PEDOT:PSS by antimonene quantum sheets doping for highly efficient OLEDs
Efficient hole injection layers (HILs) are crucial for organic light emitting diodes (OLEDs) achieving high performance. In this work, we report that semi-conductive antimonene quantum sheets (AMQSs) doped PEDOT:PSS can effectively adjust the work function from -5.2 eV to -4.9 eV, and exhibits significantly higher hole injection performance and transmittance than pure PEDOT:PSS layer. Consequently, the Ir(ppy)3-based green OLEDs adopting PEDOT:PSS:AMQSs as HIL show lower turn-on voltage of 3.0 V and achieve dramatically higher device efficiency. Particularly, the optimized AMQSs-based OLED realizes the maximum current efficiency (CE), power efficiency (PE) and external quantum efficiency (EQE) of 69.88 cd A-1, 48.28 lm W-1 and 19.91%, respectively, which are 14.86%, 68.99% and 13.32 % higher than these of the reference device. The remarkable improvements are mainly ascribed to the two-dimensional electronic structure of AMQSs which enhances the hole injection, transport capability, and boosts the light extraction efficiency. These findings point out a novel strategy to develop high-performance OLEDs by using two-dimensional quantum sheets.