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Xue S, Tang H, Shen M, Liang X, Li X, Xing W, Yang C, Yu Z. Establishing Multiple-Order Built-In Electric Fields Within Heterojunctions to Achieve Photocarrier Spatial Separation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2311937. [PMID: 38191131 DOI: 10.1002/adma.202311937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/21/2023] [Indexed: 01/10/2024]
Abstract
Hybridizing two heterocomponents to construct a built-in electric field (BIEF) at the interface represents a significant strategy for facilitating charge separation in carbon dioxide (CO2)-photoreduction. However, the unidirectional nature of BIEFs formed by various low-dimensional materials poses challenges in adequately segregating the photogenerated carriers produced in bulk. In this study, leveraging zinc oxide (ZnO) nanodisks, a sulfurization reaction is employed to fabricate Z-scheme ZnO/zinc sulfide (ZnS) heterojunctions featuring a multiple-order BIEF. These heterojunctions reveal distinctive interfacial structures characterized by two semicoherent phase boundaries. The cathodoluminescence 2D maps and density functional theory calculation results demonstrate that the direction of the multiple-order BIEF spans from ZnS to ZnO. This directional alignment significantly fosters the spatial separation of photogenerated electrons and holes within ZnS nanoparticles and enhances CO2-to-carbon monoxide photoreduction performance (3811.7 µmol h-1 g-1). The findings present a novel pathway for structurally designing BIEFs within heterojunctions, while providing fresh insights into the migratory behavior of photogenerated carriers across interfaces.
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Affiliation(s)
- Sikang Xue
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
- Fujian Science & Technology Innovation Laboratory for Chemical Engineering of China, College of Chemical Engineering, Fuzhou University, Quanzhou, 362114, P. R. China
| | - Hao Tang
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Min Shen
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Xiaocong Liang
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Xiaoyan Li
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Wandong Xing
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Can Yang
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Zhiyang Yu
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
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Xu Z, Hou B, Zhao F, Suo S, Liu Y, Shi H, Cai Z, Hill CL, Musaev DG, Mecklenburg M, Cronin SB, Lian T. Direct In Situ Measurement of Quantum Efficiencies of Charge Separation and Proton Reduction at TiO 2-Protected GaP Photocathodes. J Am Chem Soc 2023; 145:2860-2869. [PMID: 36715560 PMCID: PMC9912250 DOI: 10.1021/jacs.2c10578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Photoelectrochemical solar fuel generation at the semiconductor/liquid interface consists of multiple elementary steps, including charge separation, recombination, and catalytic reactions. While the overall incident light-to-current conversion efficiency (IPCE) can be readily measured, identifying the microscopic efficiency loss processes remains difficult. Here, we report simultaneous in situ transient photocurrent and transient reflectance spectroscopy (TRS) measurements of titanium dioxide-protected gallium phosphide photocathodes for water reduction in photoelectrochemical cells. Transient reflectance spectroscopy enables the direct probe of the separated charge carriers responsible for water reduction to follow their kinetics. Comparison with transient photocurrent measurement allows the direct probe of the initial charge separation quantum efficiency (ϕCS) and provides support for a transient photocurrent model that divides IPCE into the product of quantum efficiencies of light absorption (ϕabs), charge separation (ϕCS), and photoreduction (ϕred), i.e., IPCE = ϕabsϕCSϕred. Our study shows that there are two general key loss pathways: recombination within the bulk GaP that reduces ϕCS and interfacial recombination at the junction that decreases ϕred. Although both loss pathways can be reduced at a more negative applied bias, for GaP/TiO2, the initial charge separation loss is the key efficiency limiting factor. Our combined transient reflectance and photocurrent study provides a time-resolved view of microscopic steps involved in the overall light-to-current conversion process and provides detailed insights into the main loss pathways of the photoelectrochemical system.
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Affiliation(s)
- Zihao Xu
- Department
of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, Georgia30322, United States,ZJU-Hangzhou
Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, Zhejiang310014, China
| | - Bingya Hou
- Department
of Electrical Engineering, University of
South California, 3710 McClintock Ave, Los Angeles, California90089, United States
| | - Fengyi Zhao
- Department
of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, Georgia30322, United States
| | - Sa Suo
- Department
of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, Georgia30322, United States
| | - Yawei Liu
- Department
of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, Georgia30322, United States
| | - Haotian Shi
- Department
of Chemistry, University of South California, 3710 McClintock Ave, Los Angeles, California90089, United States
| | - Zhi Cai
- Department
of Electrical Engineering, University of
South California, 3710 McClintock Ave, Los Angeles, California90089, United States
| | - Craig L. Hill
- Department
of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, Georgia30322, United States
| | - Djamaladdin G. Musaev
- Department
of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, Georgia30322, United States,Cherry
L. Emerson Centre for Scientific Computation, Emory University, 1515 Dickey Drive, Atlanta, Georgia30322, United
States
| | - Matthew Mecklenburg
- Core Center
of Excellence in Nano Imaging (CNI), University
of South California, 814 Bloom Walk, Los Angeles, California90089, United States
| | - Stephen B. Cronin
- Department
of Electrical Engineering, University of
South California, 3710 McClintock Ave, Los Angeles, California90089, United States,Department
of Chemistry, University of South California, 3710 McClintock Ave, Los Angeles, California90089, United States,
| | - Tianquan Lian
- Department
of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, Georgia30322, United States,
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