Small molecular host based on carbazole and m-terphenyl derivatives for efficient solution processed organic light-emitting diodes

Two soluble phosphorescent host materials, 1,4-bis(3,6-di([1,1′:3′,1″:3″,1‴:3‴,1⁗-quinquephenyl]-5″-yl)-9H-carbazol-9-yl)benzene (P-mPCCP) and 1,4-bis(3,6-bis(4,4″-di-tert-butyl-[1,1′:3′,1″-terphenyl]-5′-yl)-9H-carbazol-9-yl) benzene (T-mPCCP) derived form carbazole and m-terphenyl derivatives were designed and synthesized. These two hosts exhibit good solubility in common organic solvents and possess high glass transition temperature (Tg > 160 °C) and thermal stability. P-mPCCP and T-mPCCP as the host materials doped with the guest of fac-Ir(ppy)3, we fabricated phosphorescent organic light emitting diodes (PHOLED) by spin coating process. The turn-on voltage of P-mPCCP and T-mPCCP composing device was 4.0 and 7.0 eV and showed a maximum luminance of 21,100 and 3290 cd/m2 and a maximum luminance efficiency of 15.0 and 7.6 cd/A, respectively.