Color engineering by modified oligothiophene blends

Fully tunable light emission is demonstrated with combinations of binary blends of modified oligothiophenes of high efficiency, covering the entire spectrum of colors according to the standards of the Commission International de l'Eclairage. The emission spectrum of each blend is determined by the Forster transfer when the energy separation between the highest occupied molecular orbital-lowest unoccupied molecular orbital gap of the constituent molecules is smaller than 0.56 eV. For larger energy separation, the blend emission is just given by the superposition of the emission spectra of the constituent molecules. (C) 2000 American Institute of Physics. [S0003-6951(00)03640-8].