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The treatment of CdSe nanocrystals (NCs) in a 3-amino-1-propanol (APOL)/water (v/v = 10:1) mixture at 80 degrees C in the presence of O(2) causes them to undergo a slow chemical etching process, as evidenced by spectroscopic and structural investigations. Instead of the continuous blue shift expected from a gradual decrease in NC dimensions, a bottleneck behavior was observed with distinct plateaus in the peak position of photoluminescence (PL) and corresponding maxima in PL quantum yield (i.e., 34 +/-7%). It is presently argued that such etching behavior is a result of two competitive processes taking place on the surface of these CdSe NCs: (i) oxidation of the exposed Se-sites to acidic SeO(x)() entities, which are readily solubilized in the basic APOL/H(2)O mixture, and (ii) coordination of the underlying Cd-sites with both amines and hydroxyl moieties to temporally impede NC dissolution. This is consistent with the HRTEM results, which suggest that the etched NCs adopt pyramidal morphologies with Cd-terminated facets (i.e., (0001) bases and either {011} or {21} sides) and account for the apparent resistance to etching at the plateau regions.
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http://dx.doi.org/10.1021/ja0465404 | DOI Listing |
ACS Nano
March 2025
Luminous! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.
Colloidal II-VI nanocrystals have garnered significant research attention in nonlinear optical applications due to their low-cost synthesis, photophysical tunability, and ease of device integration. Herein, we report that dual-type II CdSe/CdTe/CdSe colloidal quantum wells (CQWs) with core/crown/crown structures achieve remarkable nonlinear optical limiting capabilities driven by an exceptionally large nonlinear absorption coefficient. Open aperture -scan reveals that these dual-type II CQWs exhibit a third-order nonlinear absorption coefficient of 33.
View Article and Find Full Text PDFAnal Chim Acta
April 2025
College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin, 300457, China. Electronic address:
Background: The appearance of cigarettes produces oil spots with different sizes and shapes affect the sensory quality of cigarettes, which are caused by the oil leakage in the production of cigarettes. In the actual production of cigarettes, the mechanical components of the cigarette production line use oil in a very large number of locations, and the processing section was very long. In the event of oil contamination of cigarettes, it is a challenge to ascertain the precise location of oil leakage in mechanical components.
View Article and Find Full Text PDFInorg Chem
March 2025
Hebei Key Laboratory of Photoelectric Control on Surface and Interface, College of Science, Hebei University of Science and Technology, Shijiazhuang 050018, China.
The electronic doping of colloidal semiconductor nanocrystals presents significant potential for future device concepts in optoelectronic and spin-based technologies. Ag is gaining recognition as a novel electronic dopant in II-VI nanocrystals as it creates intragap electronic states that participate in the recombination process of photogenerated carriers within the host materials. Herein, we report the synthesis of a series of Ag-doped II-VI quantum dots (QDs) of varying sizes via a low-temperature cation exchange strategy.
View Article and Find Full Text PDFNano Lett
March 2025
Department of Physics, Jackson State University, Jackson, Mississippi 39217, United States.
Colloidal semiconductor nanorods have demonstrated potential as bright, stable, and polarized light sources. Emission of light in these and other nanocrystals proceeds through recombination of confined electron-hole pairs or excitons with tunable size-dependent resonant frequencies. Usually, their brightness is reduced by the "dark exciton"─a nonemissive state into which electron-hole pairs relax before recombining radiatively.
View Article and Find Full Text PDFNano Lett
March 2025
Center for Ultrafast Science and Technology, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Wet-chemical reactions, covering almost all solution-based synthesis in either the oil-phase or water-phase microenvironment, lead to the as-formed products with distinct morphologies, structures, and functionalities. However, crystal nucleation and growth dynamics under those microenvironments for the same material system have not been clarified. Using in situ transmission electron microscopy on the classical II-VI CdSe-based heterostructures with atomic scale resolution, notably, we revealed the formation of Au on the CdSe surface in the oil phase while the AuSe product was nucleated in the water phase.
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