Trung Nguyen Ngoc, Luu Quynh-Phuong, Son Bui Thanh, Sinh Le Hoang, Bae Jin-Young
Department of Polymer Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, Republic of Korea.
J Nanosci Nanotechnol. 2013 Jan;13(1):434-42. doi: 10.1166/jnn.2013.7081.
Our research focused on the morphological and optical properties of core/shell cadmium selenide/zinc sulfide (CdSe/ZnS) quantum dots incorporated in silicone resin. After dispersing ligand-coated quantum dots into Dow Corning two-component silicone resins (OE6630A and OE6630B at 1:4 mixing ratio by weight), the resins were cured at 150 degrees C for 1.5 hours to produce the quantum dot-silicone resin nanocomposites. The optical, morphological and thermal properties of the quantum dot incorporated in silicone resin were investigated by ultraviolet-visible, fluorescence, atomic force microscopy, field emission scanning electron microscopy, differential scanning calorimetry and thermogravimetric analysis. When the quantum dots, originally coated with trioctylamine ligand, were transferred from a chloroform solvent to methyl phenyl silicone oil and silicone resins of high viscosity, the quantum dots showed increased turbidity and lowered fluorescence intensity. Fluorescence enhancement was investigated by using various functional ligands such as poly(1, 1-dimethyl silazane) (multi-silazane), hexamethylenediamine (diamine), cysteamine (amino-thiol), triethylsilane (reactive hydrosilane), hexamethyldisilazane, nonamethyltrisilazane, octamethylcyclotetrasilazane (reactive amines). The results showed that the reactive amines were good additive ligands for enhancing the fluorescence of CdSe/ZnS quantum dots dispersed in the silicone resins, providing 1.2-2.48 Im/W and 4.2-5.56% higher luminous efficiency and photoluminescence conversion efficiency, respectively. We speculate that these reactive amines donate electrons to the surface electron traps, thereby reducing charge recombination. In addition, quantum dots aggregate to form quantum dot clusters with a relatively homogeneously dispersed in the silicone resin matrices, showing good emission properties due to surface passivation and good colloidal stability with the addition of silazane compounds to the resin. Furthermore, the addition of silazane compounds to quantum dots-silicone resin system also shows the improved thermal stability of the as-synthesized nanocomposites.
我们的研究聚焦于掺入硅树脂中的核壳结构硒化镉/硫化锌（CdSe/ZnS）量子点的形态和光学性质。将配体包覆的量子点分散到道康宁双组分硅树脂（OE6630A和OE6630B，按重量比1:4混合）中后，树脂在150℃下固化1.5小时，以制备量子点 - 硅树脂纳米复合材料。通过紫外可见光谱、荧光光谱、原子力显微镜、场发射扫描电子显微镜、差示扫描量热法和热重分析，研究了掺入硅树脂中的量子点的光学、形态和热性质。当最初用三辛胺配体包覆的量子点从氯仿溶剂转移到甲基苯基硅油和高粘度硅树脂中时，量子点的浊度增加，荧光强度降低。通过使用各种功能性配体，如聚（1,1 - 二甲基硅氮烷）（多硅氮烷）、己二胺（二胺）、半胱胺（氨基硫醇）、三乙基硅烷（反应性氢硅烷）、六甲基二硅氮烷、九甲基三硅氮烷、八甲基环四硅氮烷（反应性胺）来研究荧光增强。结果表明，反应性胺是增强分散在硅树脂中的CdSe/ZnS量子点荧光的良好添加剂配体，分别提供了1.2 - 2.48 Im/W和4.2 - 5.56%更高的发光效率和光致发光转换效率。我们推测这些反应性胺将电子提供给表面电子陷阱，从而减少电荷复合。此外，量子点聚集形成在硅树脂基质中相对均匀分散的量子点簇，由于表面钝化而显示出良好的发射性质，并且通过向树脂中添加硅氮烷化合物具有良好的胶体稳定性。此外，向量子点 - 硅树脂体系中添加硅氮烷化合物还显示出所合成纳米复合材料的热稳定性得到改善。
