Reducing Saturation‐Current Density to Realize High‐Efficiency Low‐Bandgap Mixed Tin–Lead Halide Perovskite Solar Cells
Abstract
The unsatisfactory performance of low‐bandgap mixed tin (Sn)–lead (Pb) halide perovskite subcells has been one of the major obstacles hindering the progress of the power conversion efficiencies (PCEs) of all‐perovskite tandem solar cells. By analyzing dark‐current density and distribution, it is identified that charge recombination at grain boundaries is a key factor limiting the performance of low‐bandgap mixed Sn–Pb halide perovskite subcells. It is further found that bromine (Br) incorporation can effectively passivate grain boundaries and lower the dark current density by two–three orders of magnitude. By optimizing the Br concentration, low‐bandgap (1.272 eV) mixed Sn–Pb halide perovskite solar cells are fabricated with open‐circuit voltage deficits as low as 0.384 V and fill factors as high as 75%. The best‐performing device demonstrates a PCE of >19%. The results suggest an important direction for improving the performance of low‐bandgap mixed Sn–Pb halide perovskite solar cells.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 27, 2018
- Source ID
- 10.1002/aenm.201803135
Entities
People
- Biwas Subedi
- Changlei Wang
- Chongwen Li
- Chuanxiao Xiao
- Chun‐sheng Jiang
- Dewei Zhao
- Kai Zhu
- Maxwell M Junda
- Mowafak Al‐jassim
- Nikolas J. Podraza
- Niraj Shrestha
- Randy J Ellingson
- Yanfa Yan
- Zhaoning Song
Organizations
- Air Force Research Laboratory
- National Renewable Energy Laboratory
- United States Department of Energy
- United States Naval Research Laboratory
- University of Toledo