High-efficiency Perovskite based Tandem Solar Cells with High Open-circuit Voltage

Abstract

Perovskite/organic tandem solar cells (POTSCs) offer a promising approach to sur passing the Shockley-Queisser limit by minimizing thermalization losses. However, the efficiency of POTSCs is hindered by substantial open-circuit voltage (VOC) losses in wide bandgap per ovskite solar cells (WBG PSCs), which serve as the top cells. In this work, a multi-functional hole-selective layer (mHSL) was developed by blending two functionalized molecules, 36ICzC4PA and 36MeOCzC4PA. This blend prevents aggregation, forming a uniform and high-coverage mHSL that improves hole extraction, enhances perovskite crystallinity, and suppresses both lattice strain and phase segregation, thereby maximizing VOC. As a result, WBG PSCs achieved a PCE of 18.85% with a VOC of 1.366V, when integrated into POTSCs, the PCE reached 24.73% (certified 24.19%). Compared to POTSCs, perovskite/perovskite tandem solar cells (PPTSCs) offer superior voltage matching and minimized energy losses due to their favorable bandgap alignment. Additionally, their high crystallinity and effective defect passivation contribute to enhanced carrier transport and reduced interfacial recombination, further improving efficiency and long-term stability. These ad vantages make PPTSCs a strong candidate for next-generation photovoltaics. In this presentation, I will discuss our recent results and their implications for future solar cell technologies.