A carbazole–oxadiazole diad molecule for single-emitting-component white organic light-emitting devices (WOLEDs)

The synthesis is reported of a new molecule consisting of N-phenylcarbazole linked through a butadiyne bridge to 2,5-diphenyl-1,3,4-oxadiazole. The compound shows blue photoluminescence with positive solvatochromism: e.g., λmax 401 nm in cyclohexane, 461 nm in chloroform solution (quantum yield Φf 0.55) and 428 nm in thin film, with a low intensity band extending to ca. 700 nm in films. OLEDs with a device configuration of [ITO/PEDOT:PSS (50 nm)/molecule:PVK:OXD-7 (80 nm)/Bphen (20 nm)/LiF (0.8 nm)/Al (120 nm)] were fabricated. Pure white-light emission with Commission Internationale De L'Eclairage (CIE) coordinates of (0.313, 0.330) at 13 V and good colour stability with a very small offset of coordinates (0.034, 0.033) under biases of 9–15 V has been achieved.

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