Overcoming light loss in semi-transparent ternary organic solar cells with ultra-thin metal electrodes

Organic photovoltaics (OPVs) hold promise as renewable energy sources with diverse optoelectronic applications. Research focusing on semi-transparent OPVs has gained prominence in the field of energy conversion. In this study, we investigated semi-transparent OPVs utilizing PC71BM and PC61BM as third-component materials. The addition of PC71BM improved the open-circuit voltage (VOC) and fill factor (FF) of the devices. As a result, we selected the PM6/Y6:PC71BM ternary active layer and designed two distinct semi-transparent device structures. By adopting a sequential deposition approach (pseudo-bilayer), we achieved independent control over the PM6 layer thickness, enhancing visible transmittance performance. Compared to traditional bulk heterojunction (BHJ) structures, our design exhibited superior transparency, achieving an 11.66 % power conversion efficiency (PCE) and 24.95 % maximum average visible transmittance (AVT) under optimal conditions. It is noted that our devices demonstrated exceptional photon utilization efficiency up to 2.90 %. This study significantly advances the optimization of semi-transparent OSC performance and offers new insights for developing more efficient and transparent optoelectronic devices in the future.