Improved Characteristics of CdSe/CdS/ZnS Core-Shell Quantum Dots Using an Oleylamine-Modified Process

Abstract

CdSe/CdS with ZnS/ZnO shell quantum dots (QDs) are synthesized by a one-pot method with various oleylamine (OLA) contents. The crystal structures of the QDs were analyzed by X-ray diffractometry, which showed ZnS diffraction peaks. It was represented that the ZnS shell was formed on the surface of the CdSe/CdS core. Interestingly, QDs with a high OLA concentration exhibit diffraction peaks of ZnS/ZnO. As a result, the thermal stability of QDs with ZnS/ZnO shells exhibits better performance than those with ZnS shells. In addition, the photoluminescence intensity of QDs with ZnS/ZnO shells shows a relatively slow decay of 7.1% compared with ZnS shells at 85 °C/85% relative humidity aging test for 500 h. These indicate that QDs with different OLA modifications can form ZnS/ZnO shells and have good stability in a harsh environment. The emission wavelength of QDs can be tuned from 505 to 610 nm, suitable for micro-LED display applications.

Quantum dots luminescent compounds with multimodal luminescence for fuel labeling

“…Sulfur and zinc precursors were added dropwise during the synthesis for an hour and a half to form ZnS shell. For the synthesis of quantum dots with luminescence in the short-wavelength region of the spectrum, the 'one-pot' method was used, in which all reagents are mixed at once [31][32][33][34]. To prevent the oxidation of the resulting QDs, the synthesis was carried out in an argon atmosphere, and all solvents and stabilizers were preliminarily degassed at 130 °C.…”

Quantum dots printing paste for display backlights: Preparation, characterization, and applications

“…Nonpolar ligand (oleic acid and oleamine) capped CdSe/ZnS core-shell QDs used here were incompatible with printing paste due to their different polar characteristics. [21][22][23] Aggregation and quenching were obviously found by mixing these QDs with printing paste without special treatment. To obtain better dispersion, an appropriate solvent that is compatible with both QDs and printing paste is essential.…”

Effects of Reaction Temperature and Cadmium Source on the Optical, Morphological and Cytotoxic Properties of CdSe/ZnSe Quantum Dots

“…It was also found that conjugating BSA to QDs decreased the fluorescence of the BSA, but not that of the QDs. [12] It is therefore important to study the method of synthesizing wavelength-tunable QDs using various capping agents [13,14] for superior performance at low cost. For instance, oleylamine (OLA) is a high boiling point polar substance, which has been reported to effectively cover the nanoparticles and preserve its steadiness; this property has caused this material to be widely utilized as complexing agents in the preparation of various QDs.…”

“…For instance, oleylamine (OLA) is a high boiling point polar substance, which has been reported to effectively cover the nanoparticles and preserve its steadiness; this property has caused this material to be widely utilized as complexing agents in the preparation of various QDs. [15] Chang et al 2022 [13] carried out an intensive research on CdSe/CdS with ZnS/ZnO shell QDs synthesized by a one-pot method with various oleylamine modifications where they successfully formed highly stable ZnS/ZnO shells that can withstand harsh environmentsBesides the surfactants being key in the synthesis of these QDs, various growth parameters such as the reaction time, growth temperature, pH, sources of precursors, precursor concentrations among others play a very key role in the formation of the QDs. All these aspects of colloidal QDs synthesis have been pointed out from numerous researches and also, there are still areas in which detailed study is not fully achieved.…”