Ultra-thick inverted green organic light-emitting diodes for high power efficiency over 300 lm/W

We utilize an inverted green OLED architecture with a thick hole transfer layer (HTL) composed of multi-period organic heterojunctions as well as an emitter with horizontal orientation of dipole moment to suppress SP mode loss. The waveguide and substrate mode are extracted by combining the matched high refractive index hemispherical lens on high refractive index glass substrate, Maximum forward-viewing power efficiency (PE) and external quantum efficiency (EQE) of 305.5 lm/W and 71.0% are achieved in the device with 210 nm-thick-HTL, The optical simulation show that our results are very close to the out-coupling theoretical limit. Our work provides a promising strategy to construct OLED with ultra-high PE for achieving low-power environment-friendly display and lighting applications.