Au纳米粒子增强CdTe/CdS量子点薄膜光致发光的研究

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"掺有Au纳米粒子的CdTe / CdS量子点薄膜的可控光致发光增强" 本研究论文深入探讨了掺有Au纳米粒子(CdTe/CdS量子点薄膜)的光致发光性能增强现象，并揭示了这种增强可以通过调控金属纳米粒子(MNPs)与量子点之间的间隔层厚度来实现。实验中，通过沉积Au纳米粒子和层叠自组装的胶体CdTe/CdS量子点，制备了AuNPs/CdTe/CdS量子点纳米复合薄膜。研究发现，与不含AuNPs的样品相比，掺杂了AuNPs的薄膜的光致发光(PL)强度显著提升了约16倍。 PL增强的主要原因是AuNPs的引入。光学吸收光谱分析显示，AuNPs的加入增强了AuNPs/CdTe/CdS纳米复合薄膜的吸收能力。通过有限差分时域(FDTD)模拟，研究人员观察到随着AuNPs尺寸的增加，电场的局域化效应增强，这进一步提升了量子点在AuNPs附近区域的PL强度。这种增强被认为是由于AuNPs诱导的局部电场加强，导致量子点的激子辐射效率提高。此外，通过调整间隔层的厚度，可以控制量子点与AuNPs之间的相互作用，从而调控PL增强效果。当间隔层较薄时，量子点与AuNPs之间的耦合作用更强烈，导致更大的PL增强；而增加间隔层厚度，这种耦合作用减弱，PL增强效应也随之减小。这一发现为设计具有特定光学特性的纳米复合材料提供了新的策略，并可能对光电设备、传感器以及光电子器件的性能优化产生重要影响。这项工作不仅展示了AuNPs在提升CdTe/CdS量子点薄膜光致发光性能方面的潜力，还揭示了间隔层厚度在调控这种增强效应中的关键作用。这些发现对于理解和利用纳米材料的光学性质，特别是在量子点基光电系统中的应用，具有重要的理论和实践意义。

NAN O E X P R E S S Open Access

Controllable photoluminescence enhancement of

CdTe/CdS quantum dots thin films incorporation

with Au nanoparticles

Hongyu Wang

1,2

, Ling Xu

, Renqi Zhang

, Zhaoyun Ge

, Wenping Zhang

, Jun Xu

, Zhongyuan Ma

and Kunji Chen

Abstract

Au nanoparticles (Au NPs)/CdTe/CdS QDs nanoco mposite films were fabricated by deposition of Au NPs and layer-by-layer

self-assembly of colloidal CdTe/CdS QDs. Phot oluminescence (PL) spectra showed that Au NPs incorporation resulted in an

increase of PL intensity about 16-fold compared with that of the samples without Au NPs. PL enhancement of Au NPs/

CdTe/CdS QDs nanocomposite films can be controlled by tuning the thickness of spacer layer between the metal

nanoparticles (MNPs) and QDs. Optical absorption spectra exhibited the incorporation of Au NPs boosted the absorption

of Au NPs/CdTe/CdS QDs nanocomposite films. The results of finite-difference time-domain (FDTD) simulation indicated

that the increased sizes of Au NPs resulted in stronger localization of electric field, which boosted the PL intensity of QDs

in the vicinity of Au NPs. We thought that these were mainly attributed to localized SP enhancement effects of the Au

NPs. Our experiment results demonstrated that Au NPs/QDs nanocomposite films would be a promising candidate for

optoelectronic devices application.

PACS

78.55.-m; 82.33.Ln; 68.65.Hb

Keywords: Photoluminescence; Finite-difference time-domain; Plasmon; Quantum dots

Background

Semiconductor quantum dots (QDs) have been attracted

much attention on the application of solid-state lighting

and photovoltaics due to the unique optical properties.

The use of QDs in such applications needs the investiga-

tion of obtaining highly efficient QDs. Recently, an ef-

fective approach by using the inte raction of surface

plasmon (SP) with QDs has been raised to enhance the

photoluminescence (PL) emission of QDs [1,2]. There are

two possible processes to enhance the PL emission: an in-

creased emission rate and an increased excitation rate of

the QDs, which are depended on the intensity of local

electric field near metal nanoparticles (MNPs). The overall

effect of SP at work is determined by the competition be-

tween emission enhancement, excitation enhancement,

and quenching [3]. Some research groups have demon-

strated the application of MNPs in optoelectronic devices

based on the SP resonance effects [4-7]. The effect of the

size of MNPs and the thickness of spacer layer between

MNPs and QDs on the plasmonic interaction has rarely

been demonstrated.

In this paper, the Au NPs/QDs nanocomposite films

were fabricated using a layer-by-layer self-assembly tech-

nique. The PL spectra and fluorescence decay of QDs

film were measured in the absence an d pres ence of Au

NPs. The influence of the spacer layer thickness on the

variations of PL intensity of QDs was analyzed. In

addition, the effect of the size of MNPs on the plas-

monic interaction was studied. The local electric field in

the vicinit y of Au NPs with different sizes was modeled

by our finite-difference time-domain (FDTD).

Methods

Au NPs with different sizes were formed on quartz sub-

strates by ion sputtering in a vacuum chamber and then

* Correspondence: xuling@nju.edu.cn

National Laboratory of Solid State Microstructure and School of Electronic

Science and Engineering, Nanjing University, Nanjing 210093, People’s

Republic of China

Full list of author information is available at the end of the article

Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction

in any medium, provided the original work is properly credited.

Wang et al. Nanoscale Research Letters (2015) 10:128

DOI 10.1186/s11671-015-0833-3

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