Water-Based Route to Ligand-Selective Synthesis of ZnSe and Cd-Doped ZnSe Quantum Dots with Tunable Ultraviolet A to Blue Photoluminescence
Water-Based Route to Ligand-Selective Synthesis of ZnSe and Cd-Doped ZnSe Quantum Dots with Tunable Ultraviolet A to Blue Photoluminescence
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DOI：
10.1021/la802294e
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发表时间：
2009-01-06
期刊：
影响因子：
3.9
通讯作者：
Muscat, Anthony J.
中科院分区：
文献类型：
--
作者：
Deng, Zhengtao;Lie, Fee Li;Muscat, Anthony J.
报道了一种水基合成锌硒和镉掺杂锌硒(ZnSe(ZnxCd1-xSe，0<；x<；1)量子点的方法，该量子点的光致发光峰从紫外光(UVA)到蓝光(350-490 nm)范围可调，半高宽(FWHm)为24-36 nm。使用肼(N2H4)保持无氧条件，使反应容器开放到空气中。量子点的性质通过硫醇配体、3-巯基丙酸(MPA)、硫醇酸(TGA)和L-谷胱甘肽(GSH)进行控制。在光谱的基础上，线性的三碳MPa抑制了形核和生长，得到了表面缺陷密度较高的小的ZnSe量子点。相反，TGA和GSH产生了较大的表面缺陷密度较低的ZnSe量子点。吸收光谱表明，线型双碳TGA比支化双官能团GSH生长更均匀，控制效果更好。经过20分钟的生长，高分辨率的电子显微镜图像显示，TGA包覆的ZnSe的平均直径为2.5 nm；这些纳米晶的最大吸收峰约为340 nm(3.65 eV)，禁带宽度为372 nm(3.34 eV)。通过在ZnSe量子点溶液中直接加入Cd-硫醇络合物，制备了高荧光的ZnxCd1-xSe量子点；通过改变锌与镉的比例，在蓝光范围(400-490 nm)调谐了发光峰。X射线光电子能谱分析表明，含Cd纳米晶中Se的含量比例较高，Cd-Se键具有离子性质，而不是主要的共价Zn-Se键。
A water-based route has been demonstrated for synthesizing ZnSe and Cd-doped ZnSe (ZnSe(ZnxCd1-xSe, 0 < x < 1) quantum dots (QDs) that have tunable and narrow photo luminescence (PL) peaks from the ultraviolet A (UVA) to the blue range (350-490 nm) with full-width at half-maximum (fwhm) values of 24-36 nm. Hydrazine (N2H4) was used to maintain oxygen-free conditions, allowing the reaction vessel to be open to air. The properties of the QDs were controlled using the thiol ligands, 3-mercaptopropionic acid (MPA), thiolglycolic acid (TGA), and L-glutathione (GSH). On the basis of optical spectra, linear three-carbon MPA attenuated nucleation and growth, yielding small ZnSe QDs with a high density of surface defects. In contrast, TGA and GSH produced larger ZnSe QDs with lower surface defect densities. The absorption spectra show that growth was more uniform and better controlled with linear two-carbon TGA than branched bifunctional GSH. After 20 min of growth TGA-capped ZnSe had an average diameter of 2.5 nm based on high-resolution transmission electron microscopy images; these nanocrystals had an absorbance peak maximum of approximately 340 nm (3.65 eV) and a band gap PL emission peak at 372 nm (3.34 eV). Highly fluorescent ZnxCd1-xSe QDs were fabricated by adding a Cd-thiol complex directly to ZnSe QD solutions; PL peaks were tuned in the blue range (400-490 nm) by changing the Zn to Cd ratio. The Cd-bearing nanocrystals contained proportionally more Se based on X-ray photoelectron spectroscopy, and Cd-Se bonds had ionic character, in contrast to primarily covalent Zn-Se bonds.