Improving Efficiency and Reproducibility of Perovskite Solar Cells through Aggregation Control in Polyelectrolytes Hole Transport Layer.

Here, we report that the performance of perovskite solar cells (PSCs) can be improved by aggregation control in polyelectrolytes interlayer. Through counterions tailoring and solvent optimization, the strong aggregation of polyelectrolytes P3CT-Na can be broken up by P3CT-CH3NH2. When using P3CT-CH3NH2 to replace P3CT-Na as hole transport layer, the average efficiency is greatly improved from 16.9 to 18.9% (highest 19.6%). Importantly, efficiency over 15% is obtained in 1 cm2 devices with P3CT-CH3NH2, ∼50% higher than that with P3CT-Na (10.3%). Our work demonstrates the important role of aggregation control in polyelectrolytes interlayer, providing new opportunities to promote its application in PSCs.