极化电荷设计调控纳米复合体系的能带结构  

Energy band engineering of multi-component heteronanostructures by polarization charge design

作　　者：刘研 张国桢 江俊 Yan Liu;Guozhen Zhang;Jun Jiang(Key Laboratory of Functional Molecular Solids Wuhu 241000,China;Department of Chemistry and Materials Science,Ministry of Education,College of Chemistry and Materials Science,Anhui Normal University University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]安徽师范大学化学与材料科学学院,功能分子固体教育部重点实验室,芜湖241000 [2]中国科学技术大学化学与材料科学学院,合肥230026

出　　处：《科学通报》2018年第33期3403-3411,共9页Chinese Science Bulletin

基　　金：国家重点基础研究发展计划(2014CB848900);国家自然科学基金(21473166);中国科学院前沿科学重点研究计划(QYZDB-SSW-SLH018);中央高校基本科研业务费专项资金资助

摘　　要：光生电子空穴对分离是光催化领域的关键过程和核心议题之一.本文聚焦新型光催化复合材料的设计和调控,系统地介绍了复合材料设计中通过体系能带结构的调控实现有效的电荷分离的常用手段,包括构建肖特基结、p-n结等异质结构和诱导界面电荷极化;包括构建三元复合结构ZnS-(CdS/金属),利用金属纳米颗粒修饰半导体CdS,调控CdS的能带结构,实现ZnS-CdS异质结从Ⅰ型到Ⅱ型的转化;通过在TiO_2-Ag_2S界面处复合Ag,调控体系的能带结构,设计出复合材料TiO_2-Ag-Ag_2S,实现Z-方案;设计了可以对太阳光进行全谱吸收的新型复合材料Cu2S-CdS-ZnS,并证实p-n结可以有效调控复合体系的能带结构.这些工作为纳米半导体复合材料在光电转换和光催化方面的发展提供了新的思路.Catalysis is the key to improve efficiency of materials transformation, which is crucial for sustainable development. For example, photocatalytic water splitting can use clean solar energy to produce hydrogen from water, which is clean and renewable. Unfortunately, efficiencies of photocatalysts are typically low. One of main bottlenecks lies in substantial charge recombination. Consequently, much effort has been made to promote effective charge separation with new types of photocatalytic materials. Among all available means of promoting charge separation, regulation of charge flow through heterojunction is a well-accepted and effective approach in photocatalytic materials design. This review will summarize three of representative work of heterojunction design for photocatalyst contributed by our group： A ternary semiconductor-（semiconductor/metal） model（e.g., ZnS-（CdS/Au）, ZnS-（CdS/Pd）, and Zn S-（Cd S/Pt））. In this design, a metallic nanoparticle（M） is interfaced with CdS. The difference of work function between M and CdS will drive the polarization charges flow from M to CdS until reaching equilibrium of Fermi levels. And then the Fermi level of CdS has a upshift. Therefore, the band alignment transforms from the straddling gap（type I） of ZnS-CdS heterojunction to the staggered gap（type II） of Zn S-（CdS/metal）. As a result, photogenerated electrons are kept on the surface of ZnS and metal, and holes in the CdS. Improvement of photocatalysis performance in water splitting is attained through this architecture： a Ag2S-Ag-TiO2 hybrid nanostructure. We use the wide-bandgap semiconductor TiO2 and the narrow-bandgap semiconductor Ag2S to design the Z-scheme structure, and integrate an interfacial Ag between TiO2 and Ag2S. The interfacial Ag and Ag2S have strong hybridizations at the Ag-Ag2S interface, and form Schottky junction. The polarization charge at the interface of the Schottky junction flows from Ag to Ag2S until reaching the equilibrium. This causes a upshift in the Fe

关 键 词：光催化 复合材料 肖特基结 P-N结 极化电荷 能带结构 

分 类 号：O643.3[理学—物理化学] O644.1[理学—化学]