Screening of organic semiconductors library for photovoltaic applications by density functional theory

Organic semiconductors (OS) achieved great relevance as active materials in a broad typology of devices such as light-emitting diodes or solar cells due to their peculiar electronic properties. In literature, it was demonstrated that one of the most suitable architecture to increase the power conversion efficiency (PCE) of organic solar cells is the so-called bulk heterojunction (BHJ) structure. Moreover, the most promising chemical structure for OS materials is proved to be characterized by the simultaneous presence of both donor and acceptor moieties. In order to achieve more performing PCE devices, the building of a potential chemical library could guide the fabrication of new conjugated systems. In this framework, the quantum chemical methods can be used for the screening of easily build molecular library due to their potential predictive capability. Here, we discuss this approach and show how the theoretical results, obtained from the density functional study of a novel class of donor-bridge-acceptor molecule, could provide a general guideline for the molecular design of potentially optimized photovoltaic materials with a appreciable enhanced performance in the solar power conversion.