Temperature-sensitive photoluminescence of CdSe quantum dot clusters
Temperature-sensitive photoluminescence of CdSe quantum dot clusters
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DOI：
10.1021/jp0504241
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发表时间：
2005-07-28
影响因子：
3.3
通讯作者：
Ishikawa, M
中科院分区：
文献类型：
--
作者：
Biju, V;Makita, Y;Ishikawa, M
讨论了窄尺寸、分散和纳米尺寸的硒化镉量子点聚集体（团簇）的形成及其在室温（298 K）附近的温敏光致发光（PL）光谱特性。在没有配位溶剂的情况下，CdSe量子点形成了平均直径约为27 nm的稳定团簇。使用透射电子显微镜（TEM）成像，我们鉴定了具有2-5 nm直径的单个QD与均匀尺寸的簇的关联。这些团簇在不同溶剂中的悬浮液表现出可逆的PL强度变化和PL光谱位移与温度相关。尽管封装在基质和固态中的CdSe量子点的PL强度在低温条件下显示出对温度的响应，但目前的工作首次确定了在室温以上的中等温度下显示出温度敏感的PL强度变化和光谱位移的量子点簇。温度敏感的团簇的可逆PL的变化进行了讨论，相对于量子点间界面和团簇中的偶极-偶极相互作用的电子的可逆热捕获。量子点团簇的可逆发光强度变化和光谱位移显示了开发基于量子点纳米组装的传感器的潜力。
The formation of narrow size dispersed and nanometer size aggregates (clusters) of cadmium selenide (CdSe) quantum dots (QDs) and their temperature-sensitive photolumineseence (PL) spectral properties close to room temperature (298 K) are discussed. CdSe QDs formed stable clusters with an average diameter of similar to 27 nm in the absence of coordinating solvents. Using transmission electron microscopy (TEM) imaging, we identified the association of individual QDs with 2-5 nm diameters into clusters of uniform size. A suspension of these clusters in different solvents exhibited reversible PL intensity changes and PL spectral shifts which were correlated with temperature. Although the PL intensity of CdSe QDs encapsulated in host matrixes and the solid state showed a response to temperature under cryogenic conditions, the current work identified for the first time QD clusters showing temperature-sensitive PL intensity variations and spectral shifts at moderate temperatures above room temperature. Temperature-sensitive reversible PL changes of clusters are discussed with respect to reversible thermal trapping of electrons at inter-QD interfaces and dipole-dipole interactions in clusters. Reversible luminescence intensity variations and spectral shifts of QD clusters show the potential for developing sensors based on QD nanoscale assemblies.