Band Engineering via Gradient Molecular Dopants for CsFA Perovskite Solar Cells
Abstract
Perovskites with the multi‐cation composition of cesium (Cs), methylammonium (MA), and formamidinium (FA) (CsMAFA) are pursued for their high power conversion efficiencies, but they are limited by their thermal stability. To withstand damp‐heat accelerated aging MA‐free compositions such as CsFA are of interest, but these exhibit lower carrier diffusion lengths and thus lesser performance in photovoltaic devices. A band engineering strategy that overcomes limited carrier diffusion within inverted perovskite solar cells based on CsFA is reported. A joint experimental‐computational study shows that treating the perovskite with an n‐type molecular dopant increases band bending, shaping the electric field across the active layer to overcome limited diffusive transport. Using this strategy, CsFA solar cell devices with stabilized power conversion efficiencies of 20.3%, a high value for devices using CsFA active layers, are fabricated.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 24, 2021
- Source ID
- 10.1002/adfm.202010572
Entities
People
- Andrew Harald Proppe
- Bin Chen
- Edward H. Sargent
- Hao Chen
- Mingyang Wei
- Yi Hou
- Zhijun Ning
- Ziru Huang
Organizations
- Office of Naval Research
- ShanghaiTech University
- University of Toronto