Temperature dependent photoluminescence from a cyano-substituted phenylene vinylene polymer.

We report some steady-state and time-resolved photoluminescence (PL) studies of a cyano-substituted phenlyene vinylene polymer film as a function of temperature. In contrast to simple aromatic molecules, on reducing the temperature the luminescence spectrum drops in intensity, gains structure and shifts to lower energy. While the rate of decay of the PL increases at short wavelengths and remains almost constant at long wavelengths. Using a simple kinetic scheme involving an intra-chain and an inter-chain excitation, we have successfully explained these data in terms of a delayed luminescence model.