Novel symmetrical bifacial flexible CZTSSe thin film solar cells for indoor photovoltaic applications.

Deng, Hui; Sun, Quanzhen; Yang, Zhiyuan; Li, Wangyang; Yan, Qiong; Zhang, Caixia; Zheng, Qiao; Wang, Xinghui et al. · Nat Commun · 2021

basic_science · Level V

Where this comes from

Abstract

Environment-friendly flexible Cu2ZnSn(S,Se)4 (CZTSSe) solar cells show great potentials for indoor photovoltaic market. Indoor lighting is weak and multi-directional, thus the researches of photovoltaic device structures, techniques and performances face new challenges. Here, we design symmetrical bifacial CZTSSe solar cells on flexible Mo-foil substrate to efficiently harvest the indoor energy. Such devices are fabricated by double-sided deposition techniques to ensure bifacial consistency and save cost. We report 9.3% and 9% efficiencies for the front and back sides of the flexible CZTSSe solar cell under the standard sun light. Considering the indoor environment, we verify weak-light response performance of the devices under LED illumination and flexibility properties after thousands of bending. Bifacial CZTSSe solar cells in parallel achieve the superposition of double-sided output current from multi-directional light, significantly enhancing the area utilization rate. The present results and methods are expected to expand indoor photovoltaic applications.