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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 49: Organic Electronics and Photovoltaics IV
CPP 49.2: Talk
Friday, March 22, 2024, 09:45–10:00, H 0107
Phase-field simulations of thermal annealing for all-small molecule organic solar cells — •Yasin Christian Ameslon1, Olivier Ronsin2, Christina Harreiß3, Erdmann Spiecker4, and Jens Harting5 — 1HI ERN, Nürnberg, Germany — 2HI ERN, Nürnberg, Germany — 3Nürnberg, Germany — 4IMN, Erlangen, Germany — 5HI ERN, Germany
Organic solar cells represent an emerging area in the field of photovoltaic devices. The performance relies upon the Bulk Heterojunction (BHJ) morphology whose final structure is impacted by the drying process and additional post treatment. In this study, we investigate the impact of thermal annealing (TA) on the morphology evolution of the well-studied all small molecules DRCN5T:PC71BM mixture. The objective is to determine the physical processes driving the BHJ morphology evolution. Phase field simulations are used to check the impact of the DRCN5T crystallisation related mechanisms (nucleation, growth, crystals stability, impingement, grain boundary coarsening and Ostwald ripening), of the amorphous-amorphous phase separation (AAPS), and of diffusion limitation on the final morphology. The comparison between the simulation results and the experimental data available from literature leads to following conclusions: The BHJ morphology evolution under TA is mainly due to growth of the largest DRCN5T crystals and dissolution of the smallest unstable crystals. Nucleation, impingement, Ostwald ripening, grain boundary coarsening, AAPS are not significantly active during the TA. Finally, the crystal growth could potentially be diffusion limited.
Keywords: Organic solar cell; Bulk heterojunction; Thermal annealing; Phase field; Simulation