Organic Solar Cells

Abstract

Organic-based photoconverters are subject to a considerable interest due to their promising functionalities and their potential use as alternatives to the more expensive inorganic analogues. We introduce the basic operational mechanisms, limitations and some ideas towards improving the efficiency of organic solar cells by focusing on probing the morphological/structural, dynamical, and electronic aspects of a model organic material consisting of charge-transfer discotic liquid-crystal system hexakis(n-hexyloxy)triphenylene/2,4,7 trinitro-9-fluorenone (HAT6/TNF). For the electronic ground-state investigations, neutron-scattering techniques play a key role in gaining deeper insight into structure and dynamics. These measurements are complemented by Raman and nuclear magnetic resonance probes, as well as resonant Raman and UV-vis spectroscopies that are used to explore the low-lying excited states, at the vibronic level. Synergistically, numerical simulations, either classical via empirical force fields, or first-principles via density functional theory, are used for the analysis, interpretation and predictions.