A systematic approach for development of roll-to-roll flexible solar cells

This dissertation outlines a systematic approach for developing cost-effective flexible organic and dye-sensitized solar cells. Cost effective solar cells are found at the intersection of high efficiency, low module and installation cost, and long device lifetime. Low module and installation costs are achieved by employing solution-based roll-to-roll (R2R) manufacturing on flexible substrates with low-cost materials that are abundant and non-toxic. Slot-die coating is chosen as the preferred coating technique because of its high speed, low-cost, and resulting film quality. Proof-of-concept cells are made on a research-scale coating tool developed in this work. Individual layers are studied and characterized to optimize their performance for solar cell production.;The primary challenge with these technologies is their low efficiencies and low device lifetimes. The steps required for power generation can be in competition with one another so a careful balance of cell structure is needed. Efficiency is systematically improved by first understanding the theory of how the solar cell works and developing a model to simulate the cell's performance based on measured material properties. Experimentally produced solar cells and published results validate the model. This model is used to both diagnose problems in the cell as well as to predict the performance of new cell structures. Efficiency gains from new structures are weighed against ease and speed of manufacturing. Through the use of the model, paths for organic and dye-sensitized solar cell efficiencies approaching 15% are laid out.