Effects of intermolecular interactions on the lowest excited state in luminescent conjugated polymers and oligomers

The influence of intermolecular interactions on the electronic and optical properties of conjugated compounds is discussed in relation to the use of these materials as active elements in electrooptic devices. The results of correlated quantum-chemical calculations show that intermolecular interactions strongly affect the absorption and emission properties that are characteristics of isolated conjugated chains. The emission properties of conjugated systems are significantly modified when geometry relaxation phenomena occur in the lowest excited state. The role played by molecular disorder and chemical impurities is also addressed.