Interfacial Molecular Doping of Metal Halide Perovskites for Highly Efficient Solar Cells
Abstract
Tailoring the doping of semiconductors in heterojunction solar cells shows tremendous success in enhancing the performance of many types of inorganic solar cells, while it is found challenging in perovskite solar cells because of the difficulty in doping perovskites in a controllable way. Here, a small molecule of 4,4′,4″,4″′‐(pyrazine‐2,3,5,6‐tetrayl) tetrakis (N,N‐bis(4‐methoxyphenyl) aniline) (PT‐TPA) which can effectively p‐dope the surface of FAxMA1−xPbI3 (FA: HC(NH2)2; MA: CH3NH3) perovskite films is reported. The intermolecular charge transfer property of PT‐TPA forms a stabilized resonance structure to accept electrons from perovskites. The doping effect increases perovskite dark conductivity and carrier concentration by up to 4737 times. Computation shows that electrons in the first two layers of octahedral cages in perovskites are transferred to PT‐TPA. After applying PT‐TPA into perovskite solar cells, the doping‐induced band bending in perovskite effectively facilitates hole extraction to hole transport layer and expels electrons toward cathode side, which reduces the charge recombination there. The optimized devices demonstrate an increased photovoltage from 1.12 to 1.17 V and an efficiency of 23.4% from photocurrent scanning with a stabilized efficiency of 22.9%. The findings demonstrate that molecular doping is an effective route to control the interfacial charge recombination in perovskite solar cells which is in complimentary to broadly applied defect passivation techniques.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 25, 2020
- Source ID
- 10.1002/adma.202001581
Entities
People
- Guiying Xu
- Jinsong Huang
- Peter N Rudd
- Qi Jiang
- Rongming Xue
- Yaowen Li
- Yongfang Li
- Yongli Gao
- Yun Lin
- Zhenyi Ni
Organizations
- Air Force Office of Scientific Research
- National Science Foundation
- Soochow University
- University of North Carolina at Chapel Hill
- University of Rochester