Control over the Size Effect in the Spectroscopic Properties of Zn{sub x}Cd{sub 1–} {sub x}S Colloidal Quantum Dots
- Voronezh State University (Russian Federation)
Approaches are developed for controlling the size effect in the absorption and photoluminescence properties of colloidal CdS and Zn{sub 0.5}Cd{sub 0.5}S quantum dots (QDs) in a gelatin matrix and thioglycolic acid. We analyze spectroscopic manifestations of dark Ostwald ripening and size-selective photoetching and demonstrate that the illumination of molten colloidal CdS and Zn{sub 0.5}Cd{sub 0.5}S QD solutions at a wavelength lying at the optical absorption edge in the presence of hydrogen peroxide as a catalyst for photoetching leads to a blue shift of the optical absorption and photoluminescence spectra of the QDs. Analysis of TEM images of QD samples leads us to conclude that photoetching reduces the average QD size as a consequence of the photodissolution of the CdS and Zn{sub 0.5}Cd{sub 0.5}S compounds. We demonstrate that, by contrast, heat treatment of the synthesized CdS and Zn{sub 0.5}Cd{sub 0.5}S QD sols at a temperature between 75 and 90°C leads to an increase in nanocrystal size through recrystallization, which shows up as a redshift of the optical absorption and photoluminescence spectra of the corresponding samples.
- OSTI ID:
- 22788147
- Journal Information:
- Inorganic Materials, Journal Name: Inorganic Materials Journal Issue: 5 Vol. 54; ISSN INOMAF; ISSN 0020-1685
- Country of Publication:
- United States
- Language:
- English
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