Molecular engineering of indolocarbazole–silane hosts for blue phosphorescent organic light-emitting diodes with improved thermal stability and efficiency

초록

In this study, two novel blue phosphorescent organic light-emitting diode (B-PhOLED) host materials were developed, namely 5,10-diphenyl-15-(4-(triphenylsilyl)phenyl)-10,15-dihydro-5H-diindolo[3,2-a:3′,2′-c]carbazole (DIINCz-Si) and 5-phenyl-12-(4-(triphenylsilyl)phenyl)-5,12-dihydroindolo[3,2–a]carbazole (INCz-Si). Both compounds are silane-based indolocarbazole derivatives that exhibit excellent thermal stability, with decomposition temperatures exceeding 390 °C and reaching up to 427 °C. It was demonstrated that the high triplet energies and well-aligned energy levels of these compounds facilitated efficient energy transfer to the blue dopant. These characteristics contributed to superior charge balance and low turn-on voltage in the fabricated devices. Consequently, B-PhOLEDs fabricated using these hosts achieved a maximum external quantum efficiency of 22%, a current efficiency of 41 cd/A, and a luminous efficiency of 43 lm/W. These results demonstrate that the proposed hosts possess enhanced efficiency and reduced roll-off characteristics, combined with high thermal stability, rendering them highly suitable for use in B-PhOLED applications. © 2026 The Korean Society of Industrial and Engineering Chemistry.

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