Near-Infrared absorbing A–π–D–π–A small molecule Driven by simple intramolecular noncovalent Bonds for efficient organic solar cells with enhanced visible transmittance

Abstract

Semitransparent organic solar cells are among the most promising solar cell technologies for applications in building-integrated photovoltaics (BIPV), agricultural greenhouses, and wearable energy harvesting, offering a balance between power conversion efficiency (PCE) and optical transparency. In this study, we designed and synthesized a cyclopentadithiophene (CPDT) core-based NIR absorbing NFA named CETIC for efficient organic solar cell with notably enhanced visible transparency. Employing a CPDT donor core with a 1-(dicyanomethylene)-3-indanone acceptor connected with a functional thiophene π-bridge potentially enhances the intramolecular interaction to achieve planar molecular geometry. The champion devices based on PM2:CETIC deliver an efficient PCE of 7.93 % with a Voc of 0.88 V, a Jsc of 15.52 mAcm², and a fill factor (FF) of 58 %. Our work reveals molecular design strategy by rationally establishing multiple strong noncovalent intramolecular interaction between donor and π-bridge to enhance the PCE and transparency for potential application in semitransparent organic solar cells.