Nanocomposites and nanomaterials
(Cd, Pb) iodide nanocluster films: synthesis and characterization
Bondar O.O.1, Fesych I.V.1, Lendel V.V.1, Bukivskii A.P.2, Gnatenko Y.P.2
1 Taras Shevchenko National University of Kyiv. Volodymyrska street, 60, Кyiv-01033, Ukraine. E-mail: alionka-15@ukr.net
2 Institute of Physics of the NAS of Ukraine. Prospect Nauki, 46, Kyiv-03039, Ukraine.

Pb1-xCdxI2 films can be assumed as a new perspective semiconductor materials for the development of efficient low-cost scintillator detectors, based on them, for industrial and biomedical applications. It was established that the films provide intense cathodo- and photoluminescence at room temperature [1]. 
Films (Cd, Pb)I2 with a stoichiometric ratio of 0.7 : 0.3 were obtained by the method of single-step deposition from solutions of absolute N,N-dimethylformamide of various concentrations, with further spincoating (4000 rps); film thickness ≈ 5 μm. Furthermore, have been conducted the studies of indices of changes depending on the concentration of the solutions and the method of deposition for the development of reproducible production technology. Take cognizance that all procedures were performed under open-air conditions at room temperature. 
On the basis of research, it is clear that such films have a very complex crystal structure, where PbI2 microcrystallites of submicron and micron sizes, as well as small nanoclusters, are randomly formed in the CdI2 crystal matrix [1]. The complex structure changes significantly with temperature (4.5 – 300 K).
Also, the films were characterized by XRD in the 2θ range from 10° to 60° to determine the phase purity and crystallinity. Studied that in the PbI2-doped CdI2 films two layered hexagonal 2H-polytype of PbI2 as “impurities” and a mixture of four layered hexagonal 4H-polytype and twelve layered rhombohedral 12R-polytype has been observed. The 4H polytype is the most stable structure of CdI2, both at room temperature and at higher temperatures. So, in the case of (Cd,Pb)I2 solid solution, there is a polytypic transformation of structure from 4H to 12R; nanocluster growth orients along [00l] direction. Formation of such highly oriented crystalline PbI2 hexagons in the CdI2 matrix is probably due to using N,N-Dimethylformamide.

1.	Bukivskii A.P., Gnatenko Y.P., Piryatinski Y.P., Fesych I.V., et al, Nature of Radiative Recombination Processes in Layered Heterogeneous (Pb,Cd)I2 Thick Films: Promising Scintillator Materials // Journal Hindawi – Advances in Condenced Matter Physics.-2018.-2018.-P. 5.