Red to blue OLEDs based on highly luminescent 1,3-bis(4-phenylpyridin-2-yl)-4,6-difluorobenzene platinum( ii ) complexes: the key role of substituents on the 4-phenylpyridine unit

Two tert -butyl groups on the phenyl moiety affords a suitable steric hindrance to boost the external quantum efficiency whereas the introduction of methyls ortho to the interannular C–C bond switches the colour from “emerald green” to “sky-blue”.