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.
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 quantum dots with MPA as the stabilizer. The cobalt doped ZnS quantum dots are 4 nm in diameter and are monodispersive.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2010年第1期244-248,共5页
Acta Physico-Chimica Sinica
关键词
光致发光
ZnS:Co
量子点
掺杂
制备
电化学
Photoluminescence
ZnS：Co
Quantum dots
Doping
Preparation
Electrochemistry
