物理化学学报 >> 2010, Vol. 26 >> Issue (01): 244-248.doi: 10.3866/PKU.WHXB20100124

材料物理化学 上一篇    下一篇

ZnS:Co半导体量子点的制备及其光电化学性质

杨旭, 周宏, 沈彬, 张玲   

  1. 东南大学化学化工学院, 南京 211189; 南京晓庄学院生物化工与环境工程学院, 南京 211171
  • 收稿日期:2009-06-26 修回日期:2009-11-03 发布日期:2009-12-29
  • 通讯作者: 沈彬 E-mail:binshen2000@hotmail.com

Synthesis and Optoelectrochemical Properties of ZnS:Co Semiconductor Quantum Dots

YANG Xu, ZHOU Hong, SHEN Bin, ZHANG Ling   

  1. School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, P. R. China; Biochemical and Environmental Engineering College, Nanjing Xiaozhuang University, Nanjing 211171, P. R. China
  • Received:2009-06-26 Revised:2009-11-03 Published:2009-12-29
  • Contact: SHEN Bin E-mail:binshen2000@hotmail.com

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摘要：

采用低温水热技术, 分别以柠檬酸(CA)和巯基丙酸(MPA)为稳定剂, 在70 ℃的水相中合成了单分散的, 粒子尺寸约为4 nm的ZnS:Co半导体量子点. 研究了稳定剂、Co2+掺杂剂及其掺杂量对掺杂量子点发光性能和结构的影响. XRD结果表明, Co2+离子主要掺杂在量子点表面, 对主体ZnS晶格没有影响. 当采用MPA为稳定剂, 掺杂量为5%(摩尔分数) 时, 掺杂量子点的荧光发射强度最高; 而同样掺杂量下采用CA为稳定剂时, 量子点的荧光发射强度有所下降. 循环伏安研究显示, 与空白ZnS量子点相比, Co2+离子的掺杂在ZnS的禁带中形成杂质能级, 相应地, ZnS:Co量子点的吸收边发生红移. 与未掺杂ZnS量子点相比, 掺杂量子点具有较少的表面非辐射复合中心, 因而荧光发射强度显著提高.

关键词: 光致发光, ZnS:Co, 量子点, 掺杂, 制备, 电化学

Abstract:

Co2+ doped ZnS semiconductor quantum dots (QDs) were synthesized in an aqueous solution at 70 ℃ using citric acid (CA) or mercaptopropionic acid (MPA) as a stabilizer. The as-prepared undoped and the Co2+ doped ZnS quantum dots (QDs) were characterized by UV-Vis spectrum, photoluminescence (PL) spectrum, X-ray powder diffraction (XRD), cyclic voltammetry, and transmission electron microscopy (TEM).We studied the dependence of the doped ZnS quantum dots photoluminescence on the dopant and the dopant concentration. Results show that Co2+ ions are doped mainly on the ZnS nanocrystal's surface and as a result, the band-edge and surface defect emissions of the ZnS quantum dots are substituted by a Co2+-related PL emission. The best photoluminescence intensity was obtained for the 5%(molar fraction) cobalt doped ZnS quantumdots with MPA as the stabilizer. The cobalt doped ZnS quantum dots are 4 nmin diameter and are monodispersive.

Key words: Photoluminescence, ZnS:Co, Quantumdots, Doping, Preparation, Electrochemistry