Stable and Efficient Semitransparent Organic Photovoltaics Enabled by Cathode Interface Engineering

Abstract Cathode interface engineering is a critical strategy for enhancing power conversion efficiency and device stability in semitransparent organic photovoltaics (STOPVs). Herein, a novel approach of using trithiocyanuric acid trisodium salt (TATS) is proposed to strengthen the chemical interactions between the cathode interlayer (CIL) and ultrathin silver (Ag) electrode. The introduction of TATS not only improves the conductivity of CIL, but also promotes the growth of Ag electrodes and stabilizes the morphology of Ag films, thus simultaneously improving the light utilization efficiency (LUE) and photostability of STOPVs. The LUE of STOPVs is improved from 3.62% to 3.98% after modification with TATS, and is further enhanced to 4.30% by using 35 nm molybdenum oxide as the optical structure. In addition, TATS also significantly improves the retention rate of initial efficiency from 53% to 85%, after 200 h of continuous illumination. This study offers a new perspective on achieving high‐efficiency STOPVs with enhanced stability through CIL modification strategy.