Engineering the Exciton Dissociation in Quantum‐Confined 2D CsPbBr3 Nanosheet Films |
| |
| Authors: | Zhi Yang Minqiang Wang Hengwei Qiu Xi Yao Xiangzhou Lao Shijie Xu Zhonghai Lin Luyi Sun Jinyou Shao |
| |
| Affiliation: | 1. Electronic Materials Research Laboratory (EMRL), Key Laboratory of Education Ministry, International Center for Dielectric Research (ICDR), Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, Xi'an Jiaotong University, Xi'an, China;2. Department of Physics, and Shenzhen Institute of Research and Innovation (HKU‐SIRI), The University of Hong Kong, Hong Kong, China;3. Key Laboratory of Intelligent Information Processing in Universities of Shandong, Shandong Business and Technology University, Yantai, China;4. Department of Chemical and Biomolecular Engineering and Polymer Program, Institute of Materials Science, University of Connecticut, CT, USA;5. State Key Laboratory of Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, China |
| |
| Abstract: | Recent years have witnessed a rapid development of all‐inorganic halide perovskite in optoelectronic devices. Ultrathin 2D CsPbBr3 nanosheets (NSs) with large lateral dimensions have demonstrated exceptional photophysical properties because of their analogous exciton electronic structure to quantum wells. Despite the incredible progress on device performance, the photophysics and carrier transportation parameters of quantum‐confined CsPbBr3 NSs are lacking, and the fundamental understanding of the exciton dissociation mechanism is far less developed. Here, a ligands rearrangement mechanism is proposed to explain why annealed NS films have an increased charge transfer rate and a decreased exciton binding energy and lifetime, prompting tunneling as a dominant way of exciton dissociation to separate photogenerated excitons between neighboring NSs. This facile but efficient method provides a new insight to manipulate perovskite nanocrystals coupling. Moreover, ultrathin 2D CsPbBr3 NS film is demonstrated to have a enhanced absorption cross section and high carrier mobility of 77.9 cm2 V?1 s?1, contributing to its high responsivity of 0.53 A W?1. The photodetector has a long‐term stability up to three months, which are responsible for reliable perovskite‐based device performance. |
| |
| Keywords: | all‐inorganic halide perovskites binding energy charge transfer rates exciton dissociation nanosheets |
|
|
