Hybrid Perovskite-Organic Flexible Tandem Solar Cell Enabling Highly Efficient Electrocatalysis Overall Water Splitting

Perovskite-organic tandem solar cells are attracting more attention due to their potential for highly efficient and flexible photovoltaic device. In this work, efficient perovskite-organic monolithic tandem solar cells integrating the wide bandgap perovskite (1.74 eV) and low bandgap organic active PBDB-T:SN6IC-4F (1.30 eV) layer, which serve as the top and bottom subcell, respectively, are developed. The resulting perovskite-organic tandem solar cells with passivated wide-bandgap perovskite show a remarkable power conversion efficiency (PCE) of 15.13%, with an open-circuit voltage (V_oc) of 1.85 V, a short-circuit photocurrent (J_sc) of 11.52 mA cm⁻², and a fill factor (FF) of 70.98%. Thanks to the advantages of low temperature fabrication processes and the flexibility properties of the device, a flexible tandem solar cell which obtain a PCE of 13.61%, with V_oc of 1.80 V, J_sc of 11.07 mA cm⁻², and FF of 68.31% is fabricated. Moreover, to demonstrate the achieved high V_oc in the tandem solar cells for potential applications, a photovoltaic (PV)-driven electrolysis system combing the tandem solar cell and water splitting electrocatalysis is assembled. The integrated device demonstrates a solar-to-hydrogen efficiency of 12.30% and 11.21% for rigid, and flexible perovskite-organic tandem solar cell based PV-driven electrolysis systems, respectively.