Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV16)
Publication date: 28th March 2016
Despite impressive improvements in the performance of organic and hybrid solar cells, the best devices still underperform on account of losses to incomplete charge separation and to non-geminate charge recombination. Such losses can be related to disorder in the structure and energetics of the active materials, which limits the efficiency of charge carrier collection, and to the properties of the interfaces that are essential to direct photocurrent. Here, we apply luminescence based and transient electrical characterisation techniques to evaluate the losses in open-circuit voltage for a variety of PV device types. The approacfh is based on the reciprocity between light absorption and emission in solar cell materials. We investigate the relationship between such losses and several factors: trap states in the density of states; purity of the organic semiconductor; recombination at the semiconductor-electrode interface; and unintentional doping. We use microscopic and device level modelling to better understand the observed behaviour and to seek approaches to minimise such losses.