Fully non-fused acceptors with alkylsilyl side-chain for efficient indoor organic photovoltaics

Abstract

The tetrathienoacene (4T) based fully non-fused acceptors exhibits strong spectrum compatibility with indoor light and cost competitiveness, rendering it ideal for indoor organic solar cells (OSCs). This work presents the design and synthesis of two 4T-based fully non-fused acceptors, marking their first application in indoor photovoltaics to achieve higer cost-effectiveness. Alkylsilyl side-chain engineering was employed to optimize the geometry structure of these acceptors. By elongating the length of side chains, the resulting acceptor, 4T-SiE-4F has planrer structure with improved crystallinity of blend films, which decreases the trap stats. It effectively improves the charge transport and suppress charge recombination. Consequently, an efficient and low-cost indoor photovoltaic device with power conversion efficiency of 21.41% was developed based on D18:4T-SiE-4F. Our work establishes a design framework for efficient and economically viable indoor organic photovoltaics.