Fine tuning of blue photoluminescence from indoles for device fabrication

Functionalized indoles were synthesized as blue-light emitting materials through palladium-catalyzed heteroannulation. Fine tuning of their color from violet to blue photoluminescence in solution and thin film was accomplished by placement of electron-donating and -withdrawing substituents at the C2-, C3-, and C5-positions. A device of organic light-emitting diodes was made, which exhibited the desired blue light with the Commission International de L'Eclairage (CIE) coordinates x = 0.18 and y = 0.12.