Optimization of a new system for organic solar cells is a multiparametric analysis problem which requires substantial efforts in terms of time and resources. The strong microstructure dependent performance of polymer:olymer cells makes them particularly difficult to optimize, or to translate previous knowledge from spin coating into more scalable techniques.
In this work, we study the photovoltaic performance of blade coated devices based on the promising polymer:polymer system PBDB-T and PF5-Y5 as donor and acceptor, respectively. Using our recently developed high throughput methodology, we optimize the system for multiple variables, including solvent system, active layer composition ratio and thickness, among others, by fabricating more than 500 devices with less than 24 mg of each component. As a result, the power conversion efficiency of the blade coated devices spanned from 0.08% to 6.43% in the best device. The performed statistical analysis of the large experimental data obtained shows that the solvent selection has the major impact on the final device performance, due to its influence in the active layer microstructure. As a conclusion, we propose the use of the plot of the device efficiency in the Hansen space as a powerful tool to guide solvent selection in organic photovoltaics.
Sustainable energy conversion & storage systems
High-throughput screening of blade coated polymer:polymer solar cells: solvent determines achievable performance