Tuning the color emission of thin film molecular organic light emitting devices by the solid state solvation effect

We demonstrate a general method for tuning the luminescent emission spectrum of dipolar molecules by adjusting the strength of intermolecular dipole–dipole interactions using a doped guest–host molecular organic thin film system. Spectral shifting is achieved by introducing dopants that change the local electric field in the film. This `solid state solvation effect' is used to continuously tune, by up to 75 nm, the peak emission wavelength of organic light emitting devices consisting of triarylamine host materials doped with polar luminescent dyes DCM2, aluminum tris (8-hydroxyquinoline), or both. Red, orange, yellow, green, blue, and white emission is demonstrated with the same set of organic molecules.