Electroluminescence in semiconducting conjugated polymers and oligomers: A quantum-chemical perspective

We discuss in this contribution the ability of quantum-chemical calculations to describe the essential aspects of one of the most promising applications of semiconducting conjugated polymers and oligomers, i.e., their use as active layers in light-emitting diodes (LEDs). We present an overview of the results of recent theoretical studies that we have performed on oligomers representative of polyparaphenylenevinylene and polythiophene. We mostly deal with: (i) the modelling of the linear optical properties of the conjugated polymers involved in the emitting layer, taking into account the vibronic structure; (ii) the investigation of the relative locations of, and relaxation phenomena taking place in, the lowest singlet and triplet excited states; and (iii) a general discussion of the various terms contributing to the polaron-exciton binding energy.