Guo core shell vela ge cds6/12/2023 ![]() ![]() The SILAR technique reported here can also be used for the growth of complex colloidal semiconductor nanostructures, such as quantum shells and colloidal quantum wells. The CdSe/CdS core/shell nanocrystals were found to be superior in comparison to the highly luminescent CdSe plain core nanocrystals. Colloidal Ge nanocrystals are particularly interesting in the development of near-infrared materials for applications in bioimaging, telecommunications and energy conversion. Several types of brightening phenomena were observed, some of which can further boost the PL QY of the core/shell nanocrystals. Ge nanocrystals have a large Bohr radius and a small, size-tunable band gap that may engender direct character via strain or doping. The band edge photoluminescence of the core/shell dendron-nanocrystals and box-nanocrystals were partially remained, and could be further brightened. The photoluminescence quantum yield (PL QY) of the as-prepared CdSe/CdS core/shell nanocrystals ranged from 20% to 40%, and the PL full-width at half-maximum (fwhm) was maintained between 23 and 26 nm, even for those nanocrystals for which the UV-vis and PL peaks red-shifted by about 50 nm from that of the core nanocrystals. Furthermore, the box structure of the ligands monolayer coupled with the stable inorganic CdSe/CdS core/shell nanocrystals resulted in a class of extremely stable nanocrystal/ligands complexes. The epitaxial growth of the core/shell structures was verified by optical spectroscopy, TEM, XRD, and XPS. The size distribution of the core/shell nanocrystals was maintained even after five monolayers of CdS shell (equivalent to about 10 times volume increase for a 3.5 nm CdSe nanocrystal) were grown onto the core nanocrystals. Near-infrared photoluminescence enhancement in Ge/CdS and Ge/ZnS Core/shell nanocrystals: utilizing IV/II-VI. By using the site you are agreeing to this as outlined in our privacy notice and cookie policy. 2014, Guo Y, Rowland CE, Schaller RD, Vela J. The synthesis can be readily performed on a multigram scale. This website requires cookies, and the limited processing of your personal data in order to function. For this reaction system, a relatively high temperature, about 220-240 degrees C, was found to be essential for SILAR to fully occur. The principles of SILAR were demonstrated by the CdSe/CdS core/shell model system using its shell-thickness-dependent optical spectra as the probes with CdO and elemental S as the precursors. ![]() The growth of the shell was designed to grow one monolayer at a time by alternating injections of air-stable and inexpensive cationic and anionic precursors into the reaction mixture with core nanocrystals. Successive ion layer adsorption and reaction (SILAR) originally developed for the deposition of thin films on solid substrates from solution baths is introduced as a technique for the growth of high-quality core/shell nanocrystals of compound semiconductors.
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