|
|||||
|
|
Precise Control of Perovskite Crystallization Kinetics via Sequential A-Site Doping |
|
| Authors: | Minchao Qin Haibo Xue Hengkai Zhang Hanlin Hu Kuan Liu Yuhao Li Zhaotong Qin Junjie Ma Hepeng Zhu Keyou Yan Guojia Fang Gang Li U-Ser Jeng Geert Brocks Shuxia Tao Xinhui Lu |
| Affiliation: | 1. Department of Physics, The Chinese University of Hong Kong, Shatin, 999077 Hong Kong;2. Materials Simulation and Modelling and Center for Computational Energy Research, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600MB The Netherlands;3. Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Kowloon, 999077 Hong Kong;4. Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic, 7098 Liuxian Boulevard, Shenzhen, 518055 P. R. China;5. Key Lab of Artificial Micro- and Nano-Structures of Ministry of Education of China, School of Physics and Technology, Wuhan University, Wuhan, 430072 P. R. China;6. School of Environment and Energy, State Key Laboratory of Luminescent Materials and Devices, National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, South China University of Technology, Guangzhou, 510006 P. R. China;7. National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu, 30076 Taiwan Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30013 Taiwan;8. Materials Simulation and Modelling and Center for Computational Energy Research, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600MB The Netherlands Computational Materials Science, Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, Enschede, 7500AE The Netherlands |
| Abstract: | Two-step-fabricated FAPbI3-based perovskites have attracted increasing attention because of their excellent film quality and reproducibility. However, the underlying film formation mechanism remains mysterious. Here, the crystallization kinetics of a benchmark FAPbI3-based perovskite film with sequential A-site doping of Cs+ and GA+ is revealed by in situ X-ray scattering and first-principles calculations. Incorporating Cs+ in the first step induces an alternative pathway from δ-CsPbI3 to perovskite α-phase, which is energetically more favorable than the conventional pathways from PbI2. However, pinholes are formed due to the nonuniform nucleation with sparse δ-CsPbI3 crystals. Fortunately, incorporating GA+ in the second step can not only promote the phase transition from δ-CsPbI3 to the perovskite α-phase, but also eliminate pinholes via Ostwald ripening and enhanced grain boundary migration, thus boosting efficiencies of perovskite solar cells over 23%. This work demonstrates the unprecedented advantage of the two-step process over the one-step process, allowing a precise control of the perovskite crystallization kinetics by decoupling the crystal nucleation and growth process. |
| Keywords: | crystallization kinetics perovskite solar cells reaction enthalpy sequential A-site doping two-step method |