ElectroLuminescence Efficiency in polymers based Light Emitting Diodes

Abstract

Recent experiments have shown that the electroluminescence efficiency yield of organic-based light-emitting diodes exceeds the statistical expected value. However, at the present, this behaviour is not supported by a well established theoretical picture. In addition the fundamental mechanisms involved in this efficiency enhancement, as well as the exact role of solid state effects deriving from interchain interactions have been poorly investigated. The comprehension of such issues would have a direct repercussion on the rational design of new active materials in LED technology. To unravel the mechanisms involved in the efficiency enhancement and the role of interchain interactions, the ELE-poly-LED project will give a first-principles description of the optical properties of prototypical polymer crystal geometries. In particular, we will perform the parameter-free calculation of the full excitonic structure, using plane-wave Many-Body Perturbation Theory. Such calculations need a huge computational effort due to the complexity of the problem under a theoretical point of view (many-body wave functions, non-local operators, polymers have large simulation cells, many electrons). This computational grand-challenge requires extreme supercomputing resources.