PNNL

Abstract

We report the design, synthesis, thermal, and photophysical properties of two phosphine oxide based electron transport/hole blocking materials, 2,6-bis(4-(diphenylphosphoryl)phenyl)pyridine (BM-A11) and 2,4-bis(4-(diphenyl-phosphoryl)phenyl)pyridine (BM-A10) for blue electrophosphorescent organic light emitting devices (OLEDs). The use of these materials in blue OLED with iridium (III) bis[(4,6-difluorophenyl)-pyridinato-N,C2’]picolinate (Firpic) as the phosphor was demonstrated. Using the dual host device architecture with BM-A10 as the ETM yields a maximum EQE of 8.9% with a power efficiency of 21.5 lm/W (4.0V and 35 cd/m2). When BM-A11 is used as the ETM, the maximum EQE and power efficiency improves to 14.9% and 48.4 lm/W, respectively (3.0V and 40 cd/m2).