Multifunctional Spacer in 2D/3D Wide-Bandgap Perovskite for Monolithic Perovskite/Silicon Tandem Solar Cells

To maximize the power conversion efficiency (PCE) and stability of perovskite/silicon tandem solar cells (TSCs), high-performance and stable perovskite top cells with wide-bandgaps are required. A 2D/3D wide-bandgap perovskite with a bandgap of 1.69 eV using 1H-1,2,4-triazole-1-carboximidamide (1-TzFACl) as a spacer is developed. The 2D/3D wide-bandgap perovskite shows better film quality, enhanced crystallinity, suppressed nonradiative recombination, and significantly improved phase stability. Its initial PCE (21.58%) remains above 87% after 1560 h of continuous illumination due to the insertion of Cl- in the perovskite lattice. A monolithic two-terminal perovskite/silicon TSC achieves a PCE of 25.66% with high light stability. This work provides an ingenious strategy to restrain the phase segregation in wide-bandgap perovskites, leading to effective and stable perovskite/silicon TSCs. 2D/3D wide-bandgap perovskites are successfully constructed using 1-TzFACl as a spacer. The 2D/3D perovskite exhibits better film quality, enhanced crystallinity, and suppressed nonradiative recombination losses. The optimized device based on 2D/3D perovskite shows an efficiency of 21.58% with enhanced phase stability. An efficiency of 25.66% and improved light stability are achieved for monolithic 2-terminal perovskite/silicon tandem solar cells.image (c) 2024 WILEY-VCH GmbH