Rational Design of Block-Copolymer Additives for Polymer/Small-molecule Emulsions using Experimental and Computational Approaches

Polymer Solar Cells (PSCs) have emerged as a promising technology for harvesting renewable energy from sunlight. Despite tremendous advances, the performance of PSCs is still poor compared to traditional silicon-based solar cells. Many studies have shown PSCs performance strongly depends on the morphology and the long-term thermal stability of polymer/small-molecule emulsions. Here, I implement computational and experimental methods to design and synthesize block-copolymers (BCPs) additives to intelligently control polymer emulsions. First, I use surface energy measurements along with Monte Carlo simulations to screen potential chemical building blocks to be used in the formulation of the block-copolymer. Then, I fabricate the block-copolymers based on the simulation results. The addition block-copolymers improved the performance of the solar cells in more than 100% due to significant changes in phase behavior and the thermal stability of polymer emulsion. These changes were predicted by computer simulations and confirmed by analytical characterization such as electron microscopy and X-ray diffraction. In summary, this works demonstrates that BCPs can be utilized as additives to control the morphology and improve thermal stability of Polymer Solar Cells.