SolarRevolution · Revolutionizing Understanding of Organic Solar Cell Degradation to Design Novel Stable Materials

Revolutionizing Understanding of Organic Solar Cell Degradation to Design Novel Stable Materials.

The SolarRevolution project aimed to improve understanding of bulk-heterojunction organic solar cell (OSC) performance and degradation by developing a detailed knowledge, based on quantum chemical modelling, of the chemical and physical processes involved, thereby contributing to European research efforts to design novel materials to give OSCs 20-year lifetimes and allow mass-market uptake of this low-cost, low-energy-footprint, transparent, lightweight and flexible technology. Quantum-chemical modelling of degradation mechanisms can provide detailed and experimentally-inaccessible insight which can dramatically enhance the clarity and robustness of experimental conclusions, leading to a deeper understanding of OSC performance and degradation. Diffusion of oxygen into OSCs and the subsequent photochemical reactions represent the dominant source of degradation of the photo-active layer. In this project, using quantum-chemical calculations, we aimed to contribute to the characterization of the chemical species and photoinduced processes involved both in device operation and degradation, and thereby contribute to the design of novel materials for high-performance and stable OSCs. The project forged close collaborative links with leading academic and industrial groups via host-participation in the pan-European OSC research project Establis (FP7-ITN-290022). Work has been performed towards improving understanding and prediction of the performance of solar cell materials with the completion and publication of a study assessing the predictive power of commonly used TD-DFT models when applied to the task of energy-level prediction (Front. Chem., 2013, 1, 35). A further three studies related to the prediction of optical properties of conjugated materials used in solar cell have also been completed and are in the process of being submitted. Another two studies assessing the accuracy of DFT models when applied to conjugated materials were also completed and published (J. Chem. Theory Comput., 2015, 11, 832–838 and J. Chem. Phys., 2015, 142, 224105). The fellow has also completed a project to model the conformation of polymer chains of the prototypical OSC polymer (SiPCPDTBT) in order to gain insight into its solid state morphology and optoelectronic properties. A manuscript is under preparation pending finalisation of complementary experiments by ESTABLIS collaborators. Over the course of the project, the fellow has also been engaged both in a number of research dissemination, knowledge transfer and training activities related both to the project objectives summarized above, and more broadly to his research career. These include attending and presenting at Establis scientific meetings, co-organising and delivering lectures at three workshops, and disseminating his results at eight international research conferences. The overall results and societal impact of the project is an improved ability to predict and understand the properties of OSC materials, and thus a contribution to European efforts bring this low-cost, low-energy-footprint, transparent, lightweight and flexible technology to market. Specific research and dissemination outputs are listed below.

Data: CORDIS, © European Union