Photophysical Properties of CdSe/CdS core/shell quantum dots with tunable surface composition

被引：39

作者：

Sowers, Kelly L. ^{[1
]}

Hou, Zhentao ^{[1
]}

Peterson, Jeffrey J. ^{[1
]}

Swartz, Brett ^{[1
]}

Pal, Sougata ^{[3
]}

Prezhdo, Oleg ^{[3
]}

Krauss, Todd D. ^{[1
,2
]}

机构：

[1] Univ Rochester, Dept Chem, Rochester, NY 14627 USA

[2] Univ Rochester, Inst Opt, Rochester, NY 14627 USA

[3] Univ So Calif, Dept Chem, Los Angeles, CA 90089 USA

来源：

CHEMICAL PHYSICS | 2016年 / 471卷

基金：

美国国家科学基金会;

关键词：

Nanocrystals; Surface chemistry; Nonradiative relaxation; Photoluminescence; Time-resolved; Synthesis; DENSITY-FUNCTIONAL THEORY; MEAN FREE PATHS; SEMICONDUCTOR NANOCRYSTALS; AB-INITIO; ELECTRONIC EXCITATIONS; HIGHLY LUMINESCENT; RADIATIVE DECAY; CORE; CDS; ENERGY;

D O I：

10.1016/j.chemphys.2015.09.010

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

We report the synthesis and optical characterization of core/shell CdSe/CdS quantum dots (QDs) with controlled surface composition. Using secondary phosphine chalcogenide and cadmium carboxylate precursors in an alternating layer-by-layer synthetic approach, the elemental surface composition of the quasi-type-I CdSe/CdS core/shell QDs can be repeatedly tuned from predominately cadmium to predominantly sulfur, as measured by X-ray photoelectron spectroscopy (XPS). Similar to CdS and CdSe core-only QDs, the surface composition has a significant effect on the photoluminescence (PL) quantum yield: sulfur terminated QDs exhibit quenched PL, while cadmium terminated QDs have relatively bright PL. Density-functional tight-binding calculations on CdSe/CdS core/shell clusters suggest that PL quenching for sulfur-rich surfaces is the result of a high density of hole surface states in the QD bandgap. Time-resolved PL measurements confirm the QDs' nonradiative recombination rates are strongly sensitive to the surface composition. (C) 2015 Elsevier B.V. All rights reserved.

引用

页码：24 / 31

页数：8

共 74 条

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