Blue Phosphorescent Organic Light‐Emitting Diodes Using an Exciplex Forming Co‐host with the External Quantum Efficiency of Theoretical Limit. (19th May 2014) - Shin, Hyun
Abstract A high‐efficiency blue‐emitting organic light‐emitting diode (OLED) approaching theoretical efficiency using an exciplex‐forming co‐host composed of N, N′‐dicarbazolyl‐3, 5‐benzene (mCP) and bis‐4, 6‐(3, 5‐di‐3‐pyridylphenyl)‐ 2‐methylpyrimidine (B3PYMPM) is fabricated. Iridium(III)bis[(4, 6‐difluorophenyl)‐ pyridinato‐N, C2′]picolinate (FIrpic) is used as the emitter, which turns out to have a preferred horizontal dipole orientation in the emitting layer. The OLED shows a maximum external quantum efficiency of 29.5% (a maximum current efficiency of 62.2 cd A−1), which is in perfect agreement with the theoretical prediction.