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He X, Zhong X, Si W, Zhao Z, Wang H, Zhang X, Xie Y. Interior Exciton Extraction by Spatial-Controlled Iodine Doping in BiOBr Photocatalysts. NANO LETTERS 2024; 24:6545-6552. [PMID: 38781416 DOI: 10.1021/acs.nanolett.4c00951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Extracting interior photoinduced species to the surface before their recombination is of great importance in pursuing high-efficiency semiconductor-based photocatalysis. Traditional strategies toward charge-carrier extraction, mostly relying on the construction of an electric field gradient, would be invalid toward the neutral-exciton counterpart in low-dimensional systems. In this work, by taking bismuth oxybromide (BiOBr) as an example, we manipulate interior exciton extraction to the surface by implementing iodine doping at the edges of BiOBr plates. Spatial- and time-resolved spectroscopic analyses verified the accumulation of excitons and charge carriers at the edges of iodine-doped BiOBr (BiOBr-I) plates. This phenomenon could be associated with interior exciton extraction, driven by an energy-level gradient between interior and edge exciton states, and the following exciton dissociation processes. As such, BiOBr-I shows remarkable performance in photocatalytic C-H fluorination, mediated by both energy- and charge-transfer processes. This work uncovers the importance of spatial regulation of excitonic properties in low-dimensional semiconductor-based photocatalysis.
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Affiliation(s)
- Xin He
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China Hefei, Anhui 230026, China
| | - Xia Zhong
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China Hefei, Anhui 230026, China
| | - Wen Si
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China Hefei, Anhui 230026, China
| | - Zhi Zhao
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China Hefei, Anhui 230026, China
| | - Hui Wang
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China Hefei, Anhui 230026, China
| | - Xiaodong Zhang
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China Hefei, Anhui 230026, China
| | - Yi Xie
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China Hefei, Anhui 230026, China
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Zhang J, Chen Y, Yang L, Peng X, Zhang KH, Yang Y. Correlation between Dynamics of Polaronic Photocarriers and Photoelectrochemical Performance in Mo-Doped Bismuth Vanadate. J Phys Chem Lett 2023; 14:11350-11358. [PMID: 38064648 DOI: 10.1021/acs.jpclett.3c03128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Bismuth vanadate (BiVO4) has received intense research interest due to its outstanding performance for solar water splitting, and doping it with molybdenum (Mo) ions can effectively boost photoelectrochemical performance. In this material, highly localized polarons play a key role in the photoconversion process. Herein, we uncovered the influence of Mo dopants on the dynamics of polaronic transient species using transient absorption spectroscopy. We find that the preexisting electron small polarons stemming from the thermal ionization of dopants provide additional centers to capture itinerant holes, which significantly decrease the hole lifetime. However, the introduction of dopants increases the lifetime of self-trapped excitons that arise from the binding of electron polarons and holes. The dependence of the photoelectrochemical performance of BiVO4 photoelectrodes on doping levels can be well explained by combining the dopant effects on the lifetimes of delocalized and self-trapped transient species. Our findings provide guidance for rational optimization of dopant concentration to maximize the PEC efficiency.
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Affiliation(s)
- Jinzhong Zhang
- The State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemistry, College of Chemistry & Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yihong Chen
- The State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemistry, College of Chemistry & Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Lu Yang
- The State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemistry, College of Chemistry & Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiaohui Peng
- The State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemistry, College of Chemistry & Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Kelvin Hl Zhang
- The State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemistry, College of Chemistry & Chemical Engineering, Xiamen University, Xiamen 361005, China
- Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen 361005, China
| | - Ye Yang
- The State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemistry, College of Chemistry & Chemical Engineering, Xiamen University, Xiamen 361005, China
- Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen 361005, China
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