The Synthesis Of Mn2+Doped CdSe Quantum Dots And The Study Of Synthesizing Quantum Dots By Using Se-oleylamine As Anion Precursors

Semiconductor colloidal quantum dots (QDs), which allow size depending bandgap tunablity, because of their giant divergence in electrcal, optical, magnetic properties comparing to their bulk analogues, have attract a large interests in fundamental science and technological applications, such as biology labling, photovoltaic devices and LED ect. This paper mainly focus on the the fluorescences and morphology of QDs which are resulted from the synthesis process. The backgound of â…¡â…¥ semiconductor colloidal QDs is brifely introduced, including the developing history, the widely used synthesis methods and their applications. Then, in order to verify the origin of tunable Mn2-luminescence, the maganese doped cadmium selenide was synthesied and the result was that the tunable luminescence was arising from the asymmetric crystal field but not from the lattice strain. Besides, the luminescence was affected by the doping process. Furthemore, aiming to explore the ability of Se-oleylamine being as anion precursors, several kinds of QDs were synthesized, including the simplest CdSe QDs, the CdSe with strong trap emissions and the gradient alloyed QDs. The results showed that such anion precursors facilitated the synthesis process, although the anion precursors have their intrinsic shortcomings. Also, the synthesis of branched nanocrystals of ZnSe and ZnO by using Se-oleylamine as anion precursors was reported. And the formation mechanism was proposed to relate with the behavior of oriented attachment (OA) under high temprature. Furthermore, the OA phynomenon in such system consisting of two different crystalline phase should shed som light on the non-classical crystal growth theory from a new angle. At last, The QDs are promising materials for medical digonosing, solor cells and LEDs. However, there are still some big challenges before they are commercially available, such as toxcity in biological application, how to improve the quantum yeids and energy conservation rate, the non-isovalent doping in QDs. The progress in these issues would impact our daily life trememdously.