Temperature-Dependent Photoluminescence of CdSe-Core CdS/CdZnS/ZnS-Multishell Quantum Dots

被引：231

作者：

Jing, Pengtao ^{[1
,2
]}

Zheng, Jinju ^{[1
,2
]}

Ikezawa, Micho ^{[3
]}

Liu, Xueyan ^{[1
]}

Lv, Shaozhe ^{[1
]}

Kong, Xianggui ^{[1
]}

Zhao, Jialong ^{[1
]}

Masumoto, Yasuaki ^{[3
]}

机构：

[1] Chinese Acad Sci, Key Lab Excited State Proc, Changchun Inst Opt Fine Mech & Phys, Changchun 130033, Peoples R China

[2] Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China

[3] Univ Tsukuba, Inst Phys, Tsukuba, Ibaraki 3058571, Japan

来源：

JOURNAL OF PHYSICAL CHEMISTRY C | 2009年 / 113卷 / 31期

关键词：

LIGHT-EMITTING-DIODES; NANOCRYSTALS; LUMINESCENCE; ELECTROLUMINESCENCE; CDTE;

D O I：

10.1021/jp902080p

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：

The photoluminescence (PL) spectra of CdSe-core CdS/CdZnS/ZtiS-multishell quantum dots (QDs) were studied to understand the radiative and nonradiative relaxation processes in the temperature range from 80 to 360 K. The mechanism of temperature-dependent nonradiative relaxation processes in the CdSe QDs with changing the shell structures was found to evolve from thermal activation of carrier trapping by surface defects/traps in CdSe core QDs to the multiple longitudinal-optical (LO) phonon-assisted thermal escape of carriers in the core/shell QDs. An increase in PL intensity with increasing temperature was clearly observed in the core/shell QDs with a thick US rnonoshell and a CdS/ZnCdS/ZnS multishell. The PL enhancement was considered to come from delocalization of charge carriers localized at the CdSe/CdS interface with the potential depth of similar to 30 meV. The experimental results indicated that the improvement of PL quantum efficiency in CdSe-core CdS/CdZnS/ZnS-multishell QDs could be understood in terms of the reduction of nonradiative recombination centers at the interfaces and on the surface of the multishell, as well as the confinement of electrons and holes into the QDs by an outer ZnS shell.

引用

页码：13545 / 13550

页数：6

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