Enhancing electron diffusion length in narrow-bandgap perovskites for efficient monolithic perovskite tandem solar cells.

摘要: Developing multijunction perovskite solar cells (PSCs) is an attractive route to boost PSC efficiencies above the single-junction Shockley-Queisser limit. However, commonly used tin-based narrow-bandgap perovskites have shorter carrier diffusion lengths and lower absorption coefficient than lead-based perovskites, limiting efficiency of perovskite-perovskite tandem cells. In this work, we discover that charge collection in PSCs limited by a short length electrons. Adding 0.03 molar percent cadmium ions into tin-perovskite precursors reduce background free hole concentration electron trap density, yielding long 2.72 ± 0.15 µm. It increases optimized thickness films 1000 nm, exceptional stabilized 20.2 22.7% for single junction monolithic cells, respectively. This work provides promising method enhance optoelectronic properties unleash potential Tin-based possess suitable but their limit device efficiency. Here Yang et al. add increase 2 µm reducing density.