Qu Senlin, Yuan Xin, Li Yu, Li Xingyang, Zhou Xiujuan, Xue Xiaogang, Zhang Kexiang, Xu Juan, Yuan Changlai
School of Materials Science and Engineering, Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology Guilin 541004 People's Republic of China
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou Fujian 350002 P. R. China.
Nanoscale Adv. 2021 Feb 26;3(8):2334-2342. doi: 10.1039/d1na00069a. eCollection 2021 Apr 20.
The composition and defect tolerance of CuInSe (CISe) quantum dots (QDs) provide a scaffold to design defects tailoring the elemental ratio or distributions for boosting photocatalytic H evolution (PHE). Herein, a ligand-assisted two-step aqueous method was developed to prepare defect CISe quantum dots for the first time. UV-vis, XPS, HRTEM, and HADDF investigations confirmed the typical double-absorption edges of copper vacancy defects and indium substituted at copper site defects in the structure constructed through initial synthesis tuned by Cu/In ratio and the ensued coarsening. The steady-transient PL suggested that the D-A recombination with prolonged PL lifetime dominated the emission of composition-optimized CuInSe with the Cu/In ratio of 1/4 (CISe-1/4). Further transient photocurrent and electrochemical impedance spectroscopy investigations demonstrated that surface defects in the structure favor the carriers' separation/transportation. The CISe-1/4 exhibited a superior PHE rate of 722 μmol g h, about 23 times higher than that of the initially synthesized CISe-1/4 nucleus (31 μmol g h), with a maximum apparent quantum efficiency (AQE) of 1.3%. The analysis of energy levels and the coulombic interaction energy of electron-hole ( ) based on Raman, extending UV-vis spectra investigations suggested that surface defects resulted in decreased of CISe-1/4, favoring the enhanced PHE of this structure. This work is expected to provide a reference for designing effective non-noble metal I-III-VI photocatalysts.
铜铟硒（CISe）量子点（QDs）的组成和缺陷耐受性为设计缺陷提供了一个框架，通过调整元素比例或分布来促进光催化析氢（PHE）。在此，首次开发了一种配体辅助两步水相法来制备缺陷CISe量子点。紫外可见光谱、X射线光电子能谱、高分辨透射电子显微镜和高角度环形暗场成像研究证实，在通过铜/铟比例调整初始合成及随后的粗化构建的结构中，存在典型的铜空位缺陷双吸收边和铜位点被铟取代的缺陷。稳态 - 瞬态光致发光表明，具有延长光致发光寿命的D - A复合主导了铜/铟比例为1/4（CISe - 1/4）的成分优化的CuInSe的发射。进一步的瞬态光电流和电化学阻抗谱研究表明，结构中的表面缺陷有利于载流子的分离/传输。CISe - 1/4表现出722 μmol g⁻¹ h⁻¹的优异PHE速率，约为最初合成的CISe - 1/4核（31 μmol g⁻¹ h⁻¹）的23倍，最大表观量子效率（AQE）为1.3%。基于拉曼光谱、扩展紫外可见光谱研究对电子 - 空穴（）的能级和库仑相互作用能的分析表明，表面缺陷导致CISe - 1/4的降低，有利于该结构增强的PHE。这项工作有望为设计有效的非贵金属I - III - VI族光催化剂提供参考。
