The present finding deals with a simple and low-cost fabrication of surface-passivated, brightly fluorescent zincoxide- decorated, red-emitting excitation-independent ultrafluorescent CDs, denoted as “CZnO-Dots”. Surface doping of zinc oxide significantly improved the quantum yield by up to ∼72%, and these brightly fluorescent red-emitting CZnO-Dots have been employed for the aqueous-phase photoreduction of 100 ppm hexavalent chromium(VI) to trivalent chromium(III) under the influence of sunlight irradiation. The overall utility of the prepared CZnO-Dots can be ascertained by their recyclability over seven cycles.
The doped CD with inorganic salts can apparently form a newer platform among the existing class of fluorescent optical materials such as QDs and organic dyes. The doped-soluble CD with a higher quantum yield value can provide solutions to many newer emerging and existing problems. The aqueous solutions of red-emitting brightly fluorescent CZnO-Dots with excellent photostability could compete with the already existing commercially available QDs and organic dyes for similar types of applications. Such as related to the deeper penetration ability of the fluorescent probe could directly relate the excellence of instructive image analysis. Beyond these, brightly fluorescent CZnO-Dots do have the potential for use as an excellent photocatalytic material because of their working window, which is situated in the lower wavelength region. Interestingly, further studies could reveal a vast prospective future of these solublebrightly fluorescent CZnO-Dots in the field of photocatalysis and water treatment.

Solid thin films of CdSe and CdSe/ZnS nanoparticles on different templates have been investigated under influence of power visible laser radiation. Composite structures including organic semiconductors and CdSe and CdSe/ZnS nanoparticles films have been fabricated. Luminescent and electron properties of the structures have been investigated. Luminescence quantum yield of these nanocomposite structures is shown to exceed that of the films of organic dyes by two orders of magnitude for CdSe nanoparticles with ZnS shell. As for quantum dots without the shell their luminescence quantum yield appears to fall drastically in the films and even in the matrices of organic semiconductors compared to the solution. The presence of CdSe films in multi-layer structures of polyimides leads to abrupt increase in their conductivity by several orders of magnitude. The prospects of development of photovoltaic elements and light-emitting devices including the films with high concentration of CdSe and CdSe/ZnS quantum dots are discussed.

The films with low and high concentrations of CdSe/ZnS nanoparticles have been investigated under action of visible and ultra-violet laser radiation in a wide range of power densities and temperatures. Strong shifts of absorption and luminescence spectra without increase in their width have been observed at the transition from the solution to the films of quantum dots. A complex investigation of anti-stokes luminescence of nanoparticles films has shown its thermal mechanism. Luminescence spectra of the films of quantum dots under action of ultra-violet laser radiation allow monitoring the presence of surface-active TOP and TOPO molecules in the films of quantum dots. The absence of surface-active molecules in the films with high concentration of CdSe/ZnS nanoparticles is shown. The modes of the action of power laser radiation on the films of quantum dots have been investigated. The possibility of controlling the thickness of the films by laser ablation has been shown.

CdSe/ZnS quantum dots in solution ad in condensed phase have been investigated by methods of laser induced luminescence. Anti-stokes photoluminescence (APL) of CdSe/ZnS nanoparticles in the solutions and in the films has been studied under action of laser radiation of various wavelengths. The dependencies of APL of CdSe/ZnS nanoparticles ensembles on exciting radiation intensity, temperature and quantum dots concentration have been studied. It is shown that the mechanism of APL formation in CdSe/ZnS nanoparticles is thermal.

Laser-induced luminescence of multilayer structures based on the solids of CdSe and CdSe/ZnS nanocrystals, different organic semiconductors and on the layers of organic semiconductors with embedded nanocrystals has been investigated. Drastic decrease of luminescence quantum yield is observed in the films of CdSe nanocrystals on organic semiconductors compared to those on optical glasses. The luminescence of the nanocrystals in the matrices of organic semiconductors and in multilayer structures is shown to be suppressed. The effects observed are explained by the transfer of photogenerated carriers from the nanocrystals to the molecules of organic semiconductors. The presence of the charge transfer is confirmed by a drastic increase in the conductivity (by 2 - 4 orders of magnitude) and in photo-voltaic effect at the presence of CdSe and CdSe/ZnS nanocrystals in the structures under investigation. The prospects of using the multilayer structures for development new materials for solar cells are discussed.