A systematic doping strategy to control the emission spectrum of ternary luminescent polymer blends for white emission

In order to tune the emission color of a well-mixed ternary blend of organic luminescent materials with different bandgap energies, one should practice trial and error of varying the guest concentrations because the Forster-type energy transfer among the materials takes place so easily. In this work, we suggest a systematic doping strategy to control the emission color in ternary organic/polymer luminescent blends for white emission. The strategy comprises two steps: finding out the doping concentration of each guest in its binary blend with the host at which the emission intensities of the two components are comparable and then applying the predetermined doping concentrations of the two guests to the ternary blend system. The doping concentrations were as low as below 0.1 wt% of the host. Doping of a host chromophore with a very small amount of two emitting guests did not allow the excitation energy transfer among the guests although the partial energy transfer between the host and each of the guests occurred to give white electroluminescence. (c) 2007 Elsevier B.V. All rights reserved.