468436 Model-Guided Optimization of Polymer-Electrolyte Dye Sensitized Solar Cells
First-principles modeling combined with experimental knowledge can provides a deeper understanding into DSSC material properties and processes than experimental knowledge alone. For example, Mathew et al.  used quantum chemical calculations to design a dye molecule that led to a record DSSC efficiency. This work showed that a rational, model-guided design of DSSC materials can improve the DSSC performance substantially. In our previous work, we used first-principles macroscopic mathematical models to theoretically and experimentally investigate the effects of polymer-electrolyte chemistry on the performance of polymer-electrolyte DSSCs . We determined how the polymer chemistry affects DSSC interfacial processes and subsequent affected device performance. Polymer electrolytes can reduce interfacial recombination and allow for addressing the disadvantages of liquid electrolytes such as being prone to leakage and evaporation which hinder DSSC applications.
In this work, we first conduct DSSC optimization based on a first-principles DSSC mathematical model to calculate optimal design specifications for a polymer-electrolyte DSSC and then fabricate and test the optimal cell to validate the optimality of the cell. Optimal values of DSSC design variables such as photoanode thickness, dye absorption coefficient, iodide and triiodide diffusion coefficient, irradiation intensity, and polymer chemistry are will be calculated. The mathematical model includes Bulter-Volmer kinetics along with time-dependent continuity and transport equations for all charged species—including electrons, iodide, triiodide, and lithium (the cation)— to describe the cell and to predict cell conversion efficiency and current-voltage behavior. The optimal design specifications that maximize the conversion efficiency are calculated by solving a constrained nonlinear optimization problem using a Nelder-Mead algorithm. Optimization validation will be conducted with two sets of DSSC experiments: (1) a DSSC is fabricated based on the predicted optimal design specifications, and the conversion efficiency of the fabricated cell is compared to the conversion prediction predicted by the model. (2) Cells with design specifications that are perturbed values of the theoretically-calculated optimal design specifications are fabricated and tested for conversion efficiency to investigate the true optimality of the design specifications.
 S. Mathew, A. Yella, P. Gao, R. Humphry-Baker, F. E. CurchodBasile, N. Ashari-Astani, I. Tavernelli, U. Rothlisberger, K. NazeeruddinMd, M. Grätzel, Nat Chem 2014, 6, 242.
 Y. Y. Smolin, S. Nejati, M. Bavarian, D. Lee, K. K. S. Lau, M. Soroush, Journal of Power Sources 2015, 274, 156.
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