Ab initio Molecular Dynamics of CdSe Quantum Dots Doped Glasses

We have probed the local atomic structure of the interfacial structure between the CdSe quantum dots (QDs) and sodium silicate glass matrix. Using ab initio molecular dynamics simulations, we determined the structural properties and bond length, in excellent agreement with previous experimental observations. Based on analysis of radial distribution functions, coordination environment and ring structures, we demonstrate that huge structure reconstruction occurs at the interface between the CdSe QDs and the glass matrix. The incorporation of the CdSe QDs disrupts the Na-O bonds, while stronger SiO4 tetrahedra are reformed. The existence of the glass matrix breaks the stable 4-member (4MR) and 6-member (6MR) of Cd-Se rings, and we observe a disassociated Cd atom dissolved in the glass matrix. Besides, the formation of Se-Na and Cd-O linkages is observed at the CdSe QDs/glass interface. These results significantly extend our understanding of the interfacial structure of the CdSe QDs doped glasses, and provide physical and chemical insight into the possible defect structure origin of CdSe QDs, of interest to the fabrication of the highly luminescent CdSe QDs doped glasses.