Molecularly tuned light-emitting chromophores with D-π-D and D-π-A sequences and DTT as π-center

Abstract

Light emitting (LE) chromophores with three sequential segments centered by π-center (DTT) linked by D/D or D/A pair were synthesized. In the D-π-D (dye1) and D-π-A (dye2) pair, D/A and DTT functioned as hole and electron receptors as well as electron modulators respectively. Single-layer LE devices were fabricated as dye/PVK blends. Their photoluminescence and electroluminescence properties were studied. It was found that while the photoluminescence of dyes took place through energy transfer from PVK, the electroluminescence occurred by carrier-trapping onto the dye molecule. The electroluminescence was measured in the presence of PBD. Both dyes displayed similar I-V characteristics with dye2 being slightly more efficient.