High Efficiency Red and White Organic Light Emitting Diodes based on Exciplex Host

Abstract

High efficiency monochrome red and white OLEDs were realized through the control of dopant concentration by employing the exciplex mCP:PO-T2T as host. The red OLED based on exciplex host achieved the maximum external quantum efficiency (EQE) of 21%, a 44% increase compared with traditional CBP single host. Further, the white OLED with maximum current efficiency, power efficiency and EQE of 41.2 cd/A, 43.1 lm/W, and 19.5%, respectively, was obtained by decreasing the dopant concentration to achieve the simultaneous emission of exciplex host and dopant emitter. The results demonstrate that the barrier-free charge injection, balanced charge transport/recombination, and high triplet excition harvest are responsible for the high efficiency.

Keywords

• oled
• exciplex
• host
• white
• reverse intersystem crossing