N¹,N¹,N³,N³-tetra([1,1′-biphenyl]-4-yl)-N⁵,N⁵-diphenylbenzene-1,3,5-triamine: Synthesis, optical properties and application in OLED devices as efficient hole transporting material

A hole-transporting material, N¹,N¹,N³,N³-tetra([1,1′-biphenyl]-4-yl)-N⁵,N⁵-diphenylbenzene-1,3,5-triamine (TDAB-BP), was synthesized by di([1,1′-biphenyl]-4-yl)amine and 3,5-dichloro-N,N-diphenylaniline via Buchwald-Hartwig coupling reaction. The material exhibit high hole mobility, excellent thermal and morphological stability. TDAB-based OLED device exhibited the highest performance in terms of the maximum current efficiency (9.34 cd/A), maximum power efficiency (5.89 lm/W), and maximum external quantum efficiency (6.61%), which is significantly improved than that of the standard device based on 4,4′-bis[N-(1-naphthyl)-N-phenyl-amino]-biphenyl (NPB) (7.12 cd/A, 4.90 lm/W and 5.31%). Furthermore, TDAB-BP shows a higher decomposition temperature (T_d) of 505 °C than that of NPB (418 °C). This material could be a promising hole-transporting material, especially for the high-temperature applications of OLEDs and other organic electronic devices.