"Nanotechnology and nanomaterials"

Photovoltaic properties of nanocomposites of cadmium alkanoates with semiconductor nanoparticles
Zhulai D.1, Kovalchuk A.2, Bugaychuk S.1, Klimusheva G.1, Myrna T.3, Vitusevich S.4 
1Institute of Physics, NAS of Ukraine, Kyiv, Ukraine
E-mail: dmytrozhulai@gmail.com
2Kyiv National University of Technologies and Design, Kyiv, Ukraine
3Institute of General and Inorganic Chemistry, NAS of Ukraine, Kyiv, Ukraine
4Forschungszentrum Juelich, Bioelectronics (ICS-8), Juelich, Germany 

Ionic liquid crystals of metal alkanoates in the smectic phase (+150оС) can be act as nanoreactors for the chemical synthesis of nanoparticles (NPs) of different types: semiconductors, metal and core/shell. The technology of chemical synthesis of nanoparticles directly in the matrix of an ionic liquid crystal contributes to the fact that the matrix acts as a stabilizer of nanoparticles, which leads to a small dispersion of the sizes of NPs, and the content of NPs in the matrix can reach large concentrations (up to 8 mole%) [1]. The smectic liquid crystal phase of the nanocomposite retains its layered structure under conditions of slow cooling. By such a way, anisotropic glass nanocomposites with layered smectic-like structures are formed at the room temperature with incorporated nanoparticles inside the matrix. The nanocomposits exhibits anisotropy of electric conductivity, which is directed mainly along cation-anion layers in the smectic-like matrix. The conduction mechanism is of ionic type with the activation energy ~0.8 eV for the nanocomposites with semiconductor NPs.
For the first type, we detect the photovoltaic effect both in a pure matrix and in the nanocomposites with semiconductor NPs, in "sandwich"-like cells under   illumination of samples perpendicular to the cation-anion layers by a lamp that emits in a wide range of wavelengths in the ultraviolet - blue diapason of the spectrum. Different dependences of short-circuit current are obtained from the temperature in LC mesophase and in anisotropic glasses. The magnitude of the short-circuit current increases in 3 orders of magnitude in the nanocomposites compared with the short-circuit current of the pure matrix, and the relaxation time is significantly reduced. It is established that photo-stimulated charge distribution occurs due to photo-generation of ions and transmission of electric field along the cation-anion layers of the matrix [2].
1.	Zhulai D.S, Bugaychuk S.A., Klimusheva G.V., Mirnaya T.A., Asaula V.N., Handziuk V.I ., Vitusevich S.A. Structural characteristics of different types of nanoparticles synthesized in mesomorphic metal alkanoates // Liquid Crystals, DOI: 10.1080/02678292.2016.1276979 (2017)
2.	Zhulai D, Kovalchuk A, Bugaychuk S, Klimusheva G, Mirnaya T., Vitusevich S. Photoconductivity of ionic thermotropic liquid crystal with semiconductor nanoparticles // Journal of Molecular Liquids, DOI: 10.1016/j.molliq.2017.12.097 (2017)