Modlitbová Pavlína, Klepárník Karel, Farka Zdeněk, Pořízka Pavel, Skládal Petr, Novotný Karel, Kaiser Jozef
Central European Institute of Technology (CEITEC) Brno University of Technology, Technická 3058/10, 61600 Brno, Czech Republic.
Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, Veveří 97, 60200 Brno, Czech Republic.
Nanomaterials (Basel). 2018 Jun 16;8(6):439. doi: 10.3390/nano8060439.
The purpose of this study is to investigate the time dependent growth of silica shells on CdTe quantum dots to get their optimum thicknesses for practical applications. The core/shell structured silica-coated CdTe quantum dots (CdTe/SiO₂ QDs) were synthesized by the Ströber process, which used CdTe QDs co-stabilized by mercaptopropionic acid. The coating procedure used silane primer (3-mercaptopropyltrimethoxysilane) in order to make the quantum dots (QDs) surface vitreophilic. The total size of QDs was dependent on both the time of silica shell growth in the presence of sodium silicate, and on the presence of ethanol during this growth. The size of particles was monitored during the first 72 h using two principally different methods: Dynamic Light Scattering (DLS), and Scanning Electron Microscopy (SEM). The data obtained by both methods were compared and reasons for differences discussed. Without ethanol precipitation, the silica shell thickness grew slowly and increased the nanoparticle total size from approximately 23 nm up to almost 30 nm (DLS data), and up to almost 60 nm (SEM data) in three days. During the same time period but in the presence of ethanol, the size of CdTe/SiO₂ QDs increased more significantly: up to 115 nm (DLS data) and up to 83 nm (SEM data). The variances occurring between silica shell thicknesses caused by different methods of silica growth, as well as by different evaluation methods, were discussed.
本研究的目的是研究二氧化硅壳层在碲化镉量子点上随时间的生长情况，以获得其在实际应用中的最佳厚度。采用斯特伯法合成了核/壳结构的二氧化硅包覆碲化镉量子点（CdTe/SiO₂量子点），该方法使用了由巯基丙酸共稳定的碲化镉量子点。包覆过程使用硅烷底漆（3-巯基丙基三甲氧基硅烷）以使量子点（QDs）表面亲玻璃化。量子点的总尺寸既取决于在硅酸钠存在下二氧化硅壳层生长的时间，也取决于生长过程中乙醇的存在。在最初的72小时内，使用两种主要不同的方法监测颗粒尺寸：动态光散射（DLS）和扫描电子显微镜（SEM）。比较了两种方法获得的数据，并讨论了差异的原因。在没有乙醇沉淀的情况下，二氧化硅壳层厚度增长缓慢，纳米颗粒的总尺寸在三天内从约23nm增加到近30nm（DLS数据），以及近60nm（SEM数据）。讨论了由不同的二氧化硅生长方法以及不同的评估方法导致的二氧化硅壳层厚度之间的差异。
