A 2.20 eV Bandgap Polymer Donor for Efficient Colorful Semitransparent Organic Solar Cells

摘要

Semitransparent organic solar cells (ST-OSCs) have attracted increasingattention due to their promising prospect in building-integrated photovoltaics.Generally, efficient ST-OSCs with good average visible transmittance(AVT) can be realized by developing active layer materials with light absorptionfar from the visible light range. Herein, the development of ultrawidebandgap polymer donors with near-ultraviolet absorption, paired with nearinfraredacceptors, is proposed to achieve high-performance ST-OSCs. Thekey points for the design of ultrawide bandgap polymers include constructingdonor-donor type conjugated skeleton, suppressing the quinoidal resonanceeffect, and minimizing the twist of conjugated skeleton via noncovalentconformational locks. As a proof of concept, a polymer named PBOF with anoptical bandgap of 2.20 eV is synthesized, which exhibited largely reducedoverlap with the human eye photopic response spectrum and afforded apower conversion efficiency (PCE) of 16.40% in opaque device. As a result,ST-OSCs with a PCE over 10% and an AVT over 30% are achieved withoutoptical modulation. Moreover, colorful ST-OSCs with visual aesthetics can beachieved by tuning the donor/acceptor weight ratio in active layer benefitingfrom the ultrawide bandgap nature of PBOF. This study demonstrates thegreat potential of ultrawide bandgap polymers for efficient colorful ST-OSCs.