Toward Achieving Single-Molecule White Electroluminescence from Dual Emission of Fluorescence and Phosphorescence

摘要

White organic light-emitting diodes (WOLEDs) are of great value in daily life. However, the organic white-emissive single molecules in OLEDs are rare. Herein, we report a group of carbazolyl derivatives containing thiophene (PhCz-S), selenophene (PhCz-Se), and tellurophene (PhCz-Te). Through modulating the chalcogen atom, the promoted intersystem crossing brings room-temperature phosphorescence. Moreover, PhCz-Se exhibits Commission Internationale de l'Eclairage (CIE) coordinates of (0.30, 0.29) in OLEDs measured at 4 V, which is the first example of the single-molecule WOLEDs combined with dual emission from singlet and triplet states. Also, PhCz-Te realized WOLEDs in a single emission layer at CIE coordinates of (0.34, 0.33). The theoretical and experimental results clearly show that the adjustment of heavy atoms exerts influence on the luminescent properties, which provides a new strategy for designing single-molecule WOLEDs.

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