Nanocomposites and nanomaterials
Luminescence polarization enhancement of the composite material based on Alq3 thin film and ZnO microdisks
I. Karbovnyk1, B. Turko1, B. Sadovyi1, V.S. Vasil’yev1, R. Serkiz1, Y. Kulyk1, H. Klym2, A.V. Kukhta3
1Ivan Franko National University of Lviv, Dragomanova Str., 50, Lviv, Ukraine
E-mail: ivan.karbovnyk@lnu.edu.ua
2Lviv Polytechnic National University, 12 Bandery str., Lviv, Ukraine 
3Institute for Nuclear Problems, Belarusian State University, Babruiskaya Str. 11, Minsk, Belarus

We report the data concerning fabrication, characterization, and polarized luminescence properties of the composite structure based on ZnO microdisks and Alq3 thin film. The goal of the research is to achieve the enhancement of photoluminescence intensity of Alq3 and ZnO and to demonstrate that linearly polarized light emission can be observed in this particular system. 
ZnO hexagonal microdisks were produced by the method of gas-transport reactions on the Si (100) substrate. Alq3 organic layers with the thickness less than 50 nm were thermally deposited in 10−4 Pa vacuum on pure quartz substrate and, for composite structure fabrication on Si substrate, were covered by ZnO microdisks.
The room-temperature PL emission spectra of pure Alq3 sample measured using a crossed and parallel configuration of polarizers exhibit a characteristic green emission at around 527–530 nm and weakly distinguished peak at 550 nm. The room-temperature PL emission spectra of the ZnO microdisks measured using a crossed and parallel configuration of polarizers consist of the two bands in the ultraviolet (UV) and visible regions. For the room-temperature PL spectrum of the composite structure based on ZnO microdisks and Alq3 thin film, the polarization degree estimated at 521 nm wavelength is equal to ρ = 0.12.
Based on the performed investigations, one can conclude that ZnO microdisks/ Alq3 thin film nanocomposite is a possible candidate for the emitting layer of an organic electroluminescent diodes emitting polarized light.
This research work was supported by National Research Foundation of Ukraine in the frame of the project 2020.02/0217 “Light-generating low-dimensional structures with polarized luminescence based on organic and inorganic materials”.