Tetrapyridine/triphenyltriazine-conjugated electron transporters for low-power-consumption, high-stability phosphorescent OLEDs

Abstract

The electron transport layer (ETL) is one of the three primary layers for realizing low-power-consumption organic light-emitting devices (OLEDs). However, robust wide-energy-gap ETLs with high thermal and electrical stability have rarely been explored. In this study, we newly designed and developed a series of tetrapyridine/triphenyltriazine-conjugated ETLs, named TnPyTRZ derivatives (n = 2, 3, 4), to realize a low-power-consumption OLED with high operational stability. A green phosphorescent OLED based on T3PyTRZ simultaneously realized a low turn-on voltage (V_on) at 1 cd m⁻² of 2.18 V, a high external quantum efficiency of over 24%, a high power efficiency of over 115 lm W⁻¹, and a long lifetime (LT₅₀) of 30 000 h at a high brightness of 1000 cd m⁻². Even at 1000 cd m⁻², the driving voltage was only 2.88 V. This performance is among the best reported to date.