Liu Ning, Yang Ping
J Nanosci Nanotechnol. 2014 Aug;14(8):5817-23. doi: 10.1166/jnn.2014.8870.
A hydrothermal method was used to synthesize type-II CdTe/CdSe core/shell quantum dots (QDs) using the thilglycolic acid (TGA) capped CdTe QDs as cores, which show a number of advantages. Because of the spatial separation of carriers the low excited states of CdTe/CdSe QDs, they exhibit many novel properties that are fundamentally different from the type-I QDs. On the other hand, our experiment results show that the wave function of the hole of the exciton in the CdTe core extends well into the CdSe shell. The results also reveal that a thick shell can confine the electrons inside the particles and thereby improve the PL efficiency and prolong the lifetime of the core/shell QDs. We use the UV-vis absorption and fluorescence spectrum measurements on growing particles in detail. We found that the fluorescence of the CdTe/CdSe QDs was strongly dependent on the thick of the shell and size of the core as well as the unique type-II heterostructure, which make the type-II core/shell QDs more suitable in photovoltaic or photoconduction applications.
采用水热法，以巯基乙酸（TGA）包覆的CdTe量子点为核合成了II型CdTe/CdSe核壳量子点（QDs），其具有诸多优势。由于CdTe/CdSe量子点低激发态的载流子空间分离，它们展现出许多与I型量子点根本不同的新颖特性。另一方面，我们的实验结果表明，CdTe核中激子空穴的波函数能很好地延伸到CdSe壳层中。结果还表明，厚壳层可将电子限制在粒子内部，从而提高核壳量子点的光致发光（PL）效率并延长其寿命。我们详细地对生长中的粒子进行了紫外可见吸收和荧光光谱测量。我们发现，CdTe/CdSe量子点的荧光强烈依赖于壳层厚度、核尺寸以及独特的II型异质结构，这使得II型核壳量子点更适用于光伏或光电导应用。
