SYNTHESIS AND OPTICAL PROPERTIES OF MESOMORPHIC GLASSY NANOCOMPOSITES BASED ON CADMIUM CAPRYLATE WITH CdSe / ZnS HETERONANOPARTICLES
№2

Keywords

liquid- crystalline matrix, nanocomposites, hetero-nanoparticles of metal chalcogenide, optical properties

How to Cite

Mirnaya, T., Yaremchuk, G., & Kosheliev, A. (2019). SYNTHESIS AND OPTICAL PROPERTIES OF MESOMORPHIC GLASSY NANOCOMPOSITES BASED ON CADMIUM CAPRYLATE WITH CdSe / ZnS HETERONANOPARTICLES. Ukrainian Chemistry Journal, 85(1), 13-18. https://doi.org/10.33609/0041-6045.85.1.2019.13-18

Abstract

The paper presents on the synthesis and optical properties of mesomorphic composites, based on a glassy liquid-crystalline caprylate matrix, with  CdSе/ZnS hetero-nanoparticles. The synthesis of complex core-shell semiconductor nanoparticles was carried out by fusing together a cadmium caprylate composite with CdSе nanoparticles and zinc caprylate composite with ZnS nanoparticles. The cadmium and zinc chalcogenide nanoparticles have been synthesized in molten cadmium caprylate and zinc caprylate respectively.

It has been found by optical spectroscopy that the have hetero-nanoparticles a core-shell structure. The effect of the composition (molar ratio of the components) of CdSе/ZnS hetero-nanoparticles on their spectral characteristics has been studied. It has been shown that the nanocomposites with hetero-nanoparticles are characterized by a more intense exciton fluorescence band than composites with individual CdSе or ZnS nanoparticles. It has been found that by varying the hetero-nanoparticle composition, one can change the core-shell thickness ratio and adjust thereby the absorption and emission band edge. As the number of ZnS nanoparticles in CdSе/ZnS hetero-nanoparticles increases some narrowing of the long- wavelength emission region first takes plase, which may be attributed to a reduction in the recombination of the smaller number of surface trapped exciton, and then, at a large ZnS content, a broadening of the long- wavelength emission region takes plase due to the extended CdSе/ZnS surface.

It has been found that the main  contribution to the exciton fluorescence of nanocomposites with CdSе/ZnS hetero-nanoparticles is made by cadmium selenide nanoparticles, and that zinc sulfide nanoparticles enhance exciton fluorescence, also due to decrease in surface emission. It has been shown that the nanocomposites with hetero-nanoparticles are characterized by a more intense exciton fluorescence band that the nanocomposites with individual CdSе. The highest emission is observed in the case of the 35-55 % ZnS content of the shell, and at a smaller or larger amount of ZnS, emission intensity decreases.

 

https://doi.org/10.33609/0041-6045.85.1.2019.13-18
№2

References

Pan D., Wang Q., Pang J., Jiang Sh., Ji X., An L. Semiconductor “nano-onions” with multifold alternating CdS/CdSe or CdSe/CdS structure. Chemistry of Materials – 2006. – 18: 4253.

Tessier. D., Spinicelli P., Dupont D., Patriarche G., Ithurria S., Dubertret B. Efficient exciton concentrators built from colloidal core/crown CdSe/CdS Semiconductor Nanoplatelets . Nano Letters.–2014.– 14(1) : 207.

Talapin D.V., Koeppe R., Gotzinger S., Kornowski A., Lupton J. M., Rogach A. L., Benson O., Feldmann J., Weller H. Highly emissive colloidal CdSe/CdS heterostructures of mixed dimensionality. Nano Letters. – 2003. – 3(12):1677.

Sharma S.C. A review of the electro-optical properties and their modification by radiation in polymer-dispersed liquid crystals and thin films containing CdSe/ZnS quantum dots. Materials Science and Engineering B – 2010. – 168: 5.

Klimusheva G., Mirnaya T. and Garbovskiy Y. Versatile nonlinear-optical materials based on mesomorphic metal alkanoates: design, properties, and applications. Liquid Crystals Reviews. – 2015. – 3 (1): 28.

Mirnaya T., Asaula V., Volkov S., Tolochko A., Klimusheva G. Synthesis and optical properties of liquid-crystalline nanocomposite cadmium octanoate – CdS quantum dots. Physics and Chemistry of Solid State. – 2012. – 13 (1): 131.

Lyashchova A., Dmytruk A., Dmytruk I., Klimusheva G., Mirnaya T., Asaula V. Optical absorption, induced bleaching, and photoluminescence of CdSe nanoplatelets grown in cadmium octanoate matrix. Nanoscale Research Letters. – 2014. – 9 (1): 88.

Asaula V.M., Mirnaya T.A., Yaremchuk G.G., Tolochko A.S. Mesomorphic and glass formed properties of gomologоus series of cadmium alcanoates. Ukr. Khim. Zhurn. 2011. 77 (1) : 24.

Patent UA 58140. Mirnaya T.A., Asaula V.N., Yaremchuk G.G., Volkov S.V. Method for obtaining liquid crystal glass nano-composite materials with nanoparticles of semiconductor metal sulfides. 2011.

Patent UA 69609. Mirnaya T.A., Asaula V.N., Yaremchuk G.G., Volkov S.V. Method for obtaining liquid crystal nano-composite materials with semiconductor nanoparticles CdSe. 2012.

Mirnaya T.A., Yaremchuk G.G., Tokmenko I.I., Asaula V.N. Phase diagrams of binary systems of zinc, cadmium and lead caprilates. Ukr. Khim. Zhurn.- 2013.- 79 (9) :10.

Ge M., Yue Y., Liu Y., Wu J., Dai N. Facile capping CdS and ZnS shells by thermolysis of ethylxanthate precursors for CdSe/CdS/ZnS nanocrystals. Colloids Surfaces A : Physicochem Eng. Aspects. – 2011. – 384: 574.

Lee Yu-H., Tseng Ch.-Sh., Wei Y.-L. Fabrication and characterization of CdSe/ZnS quantum dots-doped polystyrene microspheres prepared by self-assembly. Journal of Materials Research. – 2012. – 27(22): P.2829.

Downloads

Download data is not yet available.