Synthesis and properties of composite materials based on zinc oxide nanoparticles in an insulating matrix

A composite material based on zinc oxide nanoparticles synthesized by the chemical hydrothermal method and a polymer insulated matrix of sodium silicate was obtained. Free zinc oxide nanoparticles were formed by heating an equimolar solution of zinc nitrate and hexamethylenetetramine with different pH values (3–5). Nanoparticles were introduced into an aqueous sodium silicate solution and applied on a silicon substrate by centrifugation. Using scanning electron microscopy, we studied the structure and morphology of zinc oxide nanoparticles on a silicon substrate in unbound state and after their introduction into the sodium silicate matrix. It was found that the obtained particles have a hexagonal crystal lattice and a bimodal size distribution. After introduction in the matrix of sodium silicate, only smaller zinc oxide nanoparticles with an average diameter of 45 nm remain in it. Studying of the photoluminesclence spectra of a composite material, including zinc oxide nanoparticles obtained at different pH values of the initial solution, showed the presence of exciton and defectrelated photoluminescence bands with intensity’s maximums located at 383 and 590 nm, respectively. Zinc oxide nanoparticles in the stabilizing matrix of sodium silicate exhibit a higher relative intensity of exciton photoluminescence than unbound particles. The highest value of the relative intensity of exciton photoluminescence was achieved for a composite material including zinc oxide nanoparticles synthesized at pH=3,35 of the initial solution. The resulting composite materials can be used in optoelectronic and photovoltaic devices, and as an optical medium of non-cavity lasers.

1. Kim S., Dulanga R.M. Somaratne S., Whitten J.E. Effect of Adsorption on the Photoluminescence of Zinc Oxide Nanoparticles. Journal of Physical Chemistry C. 2018;122:18985-18996. DOI:10.1021/acs.jpcc.8b04715.

2. Hanemann T., Szabo D.V. Polymer-Nanoparticle Composites: From Synthesis to Modern Applications. Journal of Materials. 2010;3:3468-3472. DOI:10.3390/ma3063468.

3. Figovskiy O.L., Kudryavtcev P.G. Liquid glass and aqueous solutions of silicates as a promising basis for technological processes for the production of new nanocomposite materials. Ingenerniy Vestnik Dona. 2014:29:1-42.

4. Davood R. Synthesis and photoluminescence characterization of ZnO nanoparticles. Journal of Luminescence. 2013;134:213-218. DOI:10.1016/j.jlumin.2012.08.045.

5. Huige W., Hui W., Yijie X. An overview of lead-free piezoelectric materials and devices. Journal of Materials Chemistry C. 2018;6:12448-12462. DOI:10.1039/C8TC04515A.

6. Bacaksiz E. The effect of zinc nitrate, zinc acetate and zinc chloride precursors on investigation of structural and optical properties of ZnO thin films. Journal of Alloys and Compounds. 2008:466:447-450. DOI:10.1016/j.jallcom.2007.11.061.

7. Wang J. Synthesis and characterization of multipod, flower-like, and shuttle like ZnO frameworks in ionic liquids. Materials Letters. 2005;59:1405-1408. DOI:10.1016/j.matlet.2004.11.062.

8. Baruah S., Dutta J. Hydrothermal growth of ZnO nanostructures. Science and Technology of Advanced Materials. 2009;10:3002-3008. DOI:10.1088/1468-6996/10/1/013001.

9. Chubenko E.B. [Hydrothermal deposition of ZnO nanostructures on silicon wafer]s. Doklady BGUIR = Doklady BGUIR. 2013;2:64-68. (In Russ.)

10. Shinde K.P., Pawar R.C., Sinha B.B., Kim H.S., Oh S.S., Chung K.C. Study of effect of planetary ball milling on ZnO nanopowder synthesized by co-precipitation. Journal of Alloys and Compounds. 2014;617:408-413. DOI:10.1016/j.jallcom.2014.08.030.

11. Lu C.H., Hwang W.J., Godbole S.V. Microwave-hydrothermal synthesis and photoluminescence characteristics of zinc oxide powders. Journal of Materials Research. 2005;20:469-473. DOI:10.1557/JMR.2005.0067.