摘要
环保型CuInSe_(2)量子点具有高消光系数和宽光谱吸收范围,在光电化学催化应用中展现了良好的发展前景.然而,CuInSe_(2)量子点较低的载流子分离能力和严重的界面电荷复合降低了其光电化学性能,制约了其应用.因此,我们设计并合成了具有Ⅱ型能带排列的CuInSe_(2)/CuInS_(2)核/壳结构量子点,以促进载流子分离、减少界面缺陷;进一步通过调节In/Cu前驱体的摩尔比,产生铜空位.光物理性质研究表明,导带电子-铜空位捕获的空穴之间的辐射复合成为主要的复合方式,有效延长了载流子寿命,促进了载流子分离.因此,基于富铜空位的CuInSe_(2)/CuInS_(2)核壳量子点的光阳极获得了~8.0 mA cm^(-2)的最大饱和光电流密度,该性能是当前报道的CISe基量子点光电化学电池中的最高值之一.本工作提供了一种通过表面或内在缺陷的调控来促进光电化学应用中的电荷载流子分离和传输的有效方法.
CuInSe_(2)(CISe)quantum dots(QDs)have shown promising applications in photoelectrochemical(PEC)cells due to their nontoxicity,high extinction coefficient,and wide optical absorption range;however,their low PEC performance prevents their applications due to insufficient charge carrier separation and severe charge recombination.Herein,CISe/CuInS_(2)(CISe/CIS)core/shell structured QDs are designed and constructed to promote charge separation and diminish in-terface defects.Afterward,the copper vacancy(VCu)state of CISe/CIS QDs is enriched by modulating the precursor molar ratios of In/Cu.Therefore,the radiative recombination of the conduction band edge electrons with the VCu localized holes becomes dominant and prolongs the carrier lifetime compared with intrinsic band-to-band recombination,thus promoting charge separation.Consequently,the VCu-rich CISe/CIS QD-based photoanode shows a high photocurrent density of 8.0 mA cm^(-2),which is one of the highest values reported for CISe QD-based PEC cells.This work provides an effective approach for promoting charge carrier separation and trans-fer through surface or intrinsic defect mediation for PEC applications of I-III-VI semiconductor nanocrystals.
作者
黄征
孟杰
黄菲
余彬彬
王俊峰
杨浴民
宁甲甲
郑凯波
田建军
Zheng Huang;Jie Meng;Fei Huang;Binbin Yu;Junfeng Wang;Yumin Yang;Jiajia Ning;Kaibo Zheng;Jianjun Tian(Institute for Advanced Materials and Technology,University of Science and Technology Beijing,Beijing 100083,China;Chemical Physics and Nano,Lund University,22100,Lund,Sweden;College of Physics,Jilin University,Changchun 130012,China)
基金
supported by the National Natural Science Foundation of China (52011530123,52272134,and 51902019)
Beijing Natural Science Foundation (2222061 and 2232082)
the IndustryUniversity-Research Cooperative Education of Ministry of Education (2205064205258 and 220606429170400)
Shandong Weiqiao Pioneering Group Company Limited (BINTECH-KJZX-20220831-09 and BINTECHKJZX-20220831-29)
the support from Swedish Research Council (2021-05319)
Danish Villum Foundation Experiment Grant (50350)
Swedish Foundation for International Cooperation in Research and Higher Education (F2020/1618)。
