Synthesis, photophysical and electroluminescent properties of donor–acceptor–donor molecules based on α-cinnamoyl cyclic ketene dithioacetals

New symmetrical π-conjugated donor–acceptor–donor functionalized molecules consisting of different electron-donating moieties but same α-cinnamoyl cyclic ketene dithioacetals (CCKDA) acceptor have been synthesized. The photophysical properties of these compounds indicate that the absorption and emission result from the intramolecular charge-transfer between the donor and the acceptor. Cyclic voltammetry data show that the band gaps of the compounds vary by introducing different donor moieties. Density functional theory calculations provide an insight into the electronic structure of the molecules. The double-layer electroluminescent devices are fabricated by using these molecular materials as light emitting layer. The electroluminescent performance of the device suggests that these donor–acceptor–donor molecules can be good candidates for the application in organic light-emitting diodes.