Processing Poly(3-Hexylthiophene) Interlayer with Nonhalogenated Solvents for High-Performance and Low-Cost Quantum Dot Solar Cells

Hybrid solar cells with organic semiconductors and quantum dots (QDs) have witnessed great advance in the past few years. Nevertheless, the great majority of organic and QD hybrid solar cells generally employ halogenated solvents for the processing of organic hole-transporting interlayers. Herein, the impact of solvents on the organic semiconductor material for hybird solar cells is systematically explored. The o-xylene-processed polythiophene delivers a champion photovoltaic performance of 8.7%, which is the record value for QD and poly(3-hexylthiophene) (P3HT) hybrid solar cells. The morphology results reveal that P3HT films processed with o-XY present the moderate morphology and characteristic length scales, enabling the high photovoltaic performance. Moreover, the relationships between solvents, molecular stacking, film morphology, and photovoltaic performance are built to offer the guideline of solvents screening for these hybrid solar cells. Moreover, the great superiority of nonhalogenated solvents in fabricating high-performance optoelectronic devices with low hazards is demonstrated.