![]() In addition, for traditional bare QDs, surface trap states/defects are unavoidable due to the small size and large specific surface area, which influence their optical properties. This structural difference is subtle, thus it is difficult to synthesize nanocrystals with perfect crystallinity. In the ZB structure, the lattice plane follows an ABCABC stacking along the direction, while in the WZ structure, it follows an ABABAB stacking along the direction. In these two structures, each cation is coordinated with four counter-ions in the tetrahedral configuration and the local coordination and bond length are identical, while the stacking sequence of the two structures is different. As the most studied QDs, those with CdX (X = Se, S, Te) composition may crystallize in two different structures, that is, the cubic zincblende (ZB) and the hexagonal wurtzite (WZ) structure. The results define an approach to characterize the heterostructure of two materials with the same crystalline structure and cations.Ĭolloidal semiconductor quantum dots (QDs) have been widely studied for applications in solar cells, luminescent solar concentrators, photocatalysis, and other optoelectronic devices due to their high quantum yield, size/chemical composition tunable absorption and emission spectra, and solution processability. As the shell thickness further increases, a sharp interface appears. For thick-shelled QDs, the lattice spacing is different at the core and shell regions, while the heterostructured interface is still coherent and cannot be clearly imaged. For thin-shelled QDs, an ideal coherent interface forms between core and shell due to the small lattice mismatch, and the lattice spacing remains unchanged at the core and shell regions. By examining changes in lattice spacing in an individual quantum dot, the atomic interface is identified. Herein, high-resolution transmission electron microscopy, high-angle annular dark-field imaging, and energy-dispersive X-ray spectroscopy elemental mapping are combined to characterize the structure and identify the interface in the QDs with different CdS shell thicknesses. However, since CdSe and CdS have the same crystal structure, same cations, and similar lattice parameters, it is very challenging to image the interface. DiagNano™ Cd-Based QDs exhibit high external quantum efficiency (EQE), the EQEs of red- (R-), green- (G-), and blue- (B-) QLEDs are higher than 18%, 15% and 8%, respectively.Quantum dots (QDs) have been widely studied in recent years, due to their architecture which allows to tailor properties by controlling structure and composition. Oleic Acid Cd-Based Electroluminescent QDs have been extensively explored for applications in display and lighting due to their unique merits of high color saturation, tunable emission color, high brightness, and simple solution processability.Oleic Acid CdSe/ZnS QDs (DNP-X) are CdSe/ZnS core/shell quantum dots coated with oleic acid, with the emission peaks ranging from 460 nm to 660 nm, quantum yield ≥ 80%.Octadecylamine CdSe/ZnS QDs are CdSe/ZnS core/shell quantum dots coated with octadecylamine (ODA), with the emission peaks ranging from 500 nm to 645 nm, quantum yield > 50%.GSH CdSe/ZnS QDs are Glutathione (GSH) CdSe/ZnS core/shell quantum dots, with the emission peaks ranging from 500 nm to 620 nm, quantum yield > 75%.MUA-COOH CdSe/ZnS QDs are CdSe/ZnS core/shell quantum dots coated with carboxyl, with the emission peaks ranging from 530 nm to 640 nm.PEG-COOH CdSe/ZnS QDs are Carboxyl PEG functionalized CdSe/ZnS core/shell quantum dots, with the emission peaks ranging from 500 nm to 625 nm, quantum yield > 75%. ![]() PEG-NH 2 CdSe/ZnS QDs are Amine PEG functionalized CdSe/ZnS core/shell quantum dots, with the emission peaks ranging from 500 nm to 660 nm, quantum yield ≥ 70%.MPA-COOH CdSe/ZnS QDs are 3-Mercaptopropionic acid (MPA) functionalized CdSe/ZnS core/shell quantum dot, with the emission peaks ranging from 500 nm to 625 nm, quantum yield > 70%.CD Bioparticles provides different kinds of CdSe/ZnS Quantum Dots including, Our CdSe/ZnS quantum dots can be used in highly sensitive cellular imaging, drug delivery and light emitting devices. Through surface passivation of high bandgap ZnS shell, low luminescence efficiency caused by defects and surface-trap states can be significantly minimized. Our CdSe/ZnS quantum dots are gradient alloyed semiconductor materials with size dependent optical/electronic properties, high fluorescence efficiency, low toxicity and easy cell absorb. CD Bioparticles provides CdSe/ZnS core-shell semiconductor quantum dots with emission range from 500 nm to 650 nm. ![]()
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