Enhancing electron diffusion length in narrow-bandgap perovskites for efficient monolithic perovskite tandem solar cells
Abstract
Developing multijunction perovskite solar cells (PSCs) is an attractive route to boost PSC efficiencies to 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 the efficiency of perovskite-perovskite tandem solar cells. In this work, we discover that the charge collection efficiency in tin-based PSCs is limited by a short diffusion length of electrons. Adding 0.03 molar percent of cadmium ions into tin-perovskite precursors reduce the background free hole concentration and electron trap density, yielding a long electron diffusion length of 2.72 ± 0.15 µm. It increases the optimized thickness of narrow-bandgap perovskite films to 1000 nm, yielding exceptional stabilized efficiencies of 20.2 and 22.7% for single junction narrow-bandgap PSCs and monolithic perovskite-perovskite tandem cells, respectively. This work provides a promising method to enhance the optoelectronic properties of narrow-bandgap perovskites and unleash the potential of perovskite-perovskite tandem solar cells.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 03, 2019
- Source ID
- 10.1038/s41467-019-12513-x
Entities
People
- Bo Chen
- Haotong Wei
- Jingjing Zhao
- Jinsong Huang
- Joseph J. Berry
- Kang L. Wang
- Matthew C. Beard
- Peter N Rudd
- Severin N. Habisreutinger
- Xihan Chen
- Xun Xiao
- Yehao Deng
- Zhenhua Yu
- Zhenyi Ni
- Zhibin Yang