Tunable white light generation by modified oligothiophenes blends

Fully tunable binary blends have been fabricated by combining a new class o f modified oligothiophenes with photoluminescence efficiency up to 70 %. Th e blends cover the entire spectrum of colors according to the standards of the Commission International de l'Eclairage (CIE), including white and purp le. We demonstrate that the emission spectrum of the blend is determined by the Forster transfer when the energy separation between the HOMO-LUMO gap of the constituting molecules is smaller than 0.56 eV. For larger energy se paration, the blend emission is just given by the superposition of the emis sion spectra of the constituting molecules.