Broad wavelength modulating and design of organic white diode based on lighting by using exciplex emission from mixed acceptors

Abstract

Modulating electroluminescent (EL) spectra from interfacial exciplex emissions were observed by varying the ratios of two acceptors of exciplex-type devices in which the emissive wavelengths were tuned from 530to656nm. In the devices 4,4′,4″-tris[3-methyl-pheny(phenyl)amino]triphenylamine and (bathocuproine: scdolinium-(dibenzoyl-methane)3bathophenyl-phenathroline) mixtures were used as donor and acceptor materials, respectively. In terms of the exciplex broad band emission a white organic light emitting diode was demonstrated by skillfully designing the structure when blue subband was subjoined in the white spectrum. The white device behaves the Commission Internationale de l’Eclairage coordinates of (0.32, 0.35) with higher color stability at various biases, a color rendering index of 90.4, and a maximum luminance of 425cd∕m2, respectively, although the EL efficiency needs to be further improved. The emission mechanism of the broad exciplex band formed by two mixed acceptors was also discussed.