Chelating agent and substrate effect on hydrothermal growth of Yb3+/Er3+ doped NaYf4 film

We report simultaneous crystal growth and deposition of upconverting Yb3+/Er3+ doped NaYF4 film (UCF) on conducting and non-conducting substrates by one-step hydrothermal method. The characteristics such as film topography, morphology, crystallographic phase and upconverting luminescence intensity were found to depend both on the chelating agent and nature of the substrate. The characteristics of the prepared films varied interestingly when either the chelating agent or the substrate was changed. The upconversion emission intensities were found to increase with decreasing film roughness. Further, current investigation demonstrated that the NaYF4 films deposited using EDTA or DTPA chelating agents on ITO substrate and EGTA chelating agent on PG substrate were more uniform and resulted in greater upconverted emission intensities. We envision plausible use of current technology in the development of affordable optical platforms for several optoelectronic applications.

Directional crystallization of C8-BTBT-C8 thin films in a temperature gradient

A directional crystallization of C8-BTBT-C8 in a temperature gradient reduces film roughness and improves in-plane alignment.

Distribution of profiles and macroparticles in coatings obtained by continuous cathodic arc using a straight magnetic concentrator

Thin films of Ti and Cu were deposited on 316 stainless steel substrates by the continuous cathodic arc technique with magnetic concentrator in a straight duct. Samples obtained at different cathode-substrate distances, for positions within the magnetic concentrator. The morphology of the surface was determined by electron scanning microscopy (SEM). The average thickness of the films was measured from the deposited mass; the profiles of the films were also studied from measurements with a Calotest in different points of the samples and with a profilometer, the coefficient of friction and wear were characterized with a tribometer; the hardness with a nanoindenter. The results showed that the average thickness increased by the action of the magnetic concentrator, although this causes the samples to have a central region of maximum thickness and that the thickness decreased up to 50% in a radius of about 1 cm. The films were rough with presence of macroparticles. The number of macroparticles, the film roughness and the deposition rate were also analyzed; the deposition rate depended on the axial position inside the duct. The number of macroparticles diminished with increasing axial position, the friction coefficient and wear rate diminished when the substrate was placed farther from the cathode, inside the magnetic duct. The hardness value measured with a nanoindenter is about the order as the reported in the literature; the lowest coefficients of friction, the least wear and the highest values of hardness were obtained in the region where the magnetic field is highest.

A brief review on the techniques used for the enhancement of luminescence of red emitting thin film

In the past few years, red emitting thin film activated by Eu3+ has received much attention. Europium has a peculiar property that it exhibits both types of emission on the basis of their valencies. In this review, we try to make a full list of known methods which may be useful for the enhancement of luminescence. It has been found that luminescence can be enhanced by increasing substrate temperature, film roughness, changing the morphology etc. Finally we discuss the mechanism of co-doping with different elements for the enhancement of luminescence.

Исследование упругих свойств пленок SiC, синтезированных на подложках Si методом замещения атомов

The elastic properties of a nanoscale film of silicon carbide grown on a silicon substrate by atom substitution are studied. For the first time, the Young's modulus of nanoscale silicon carbide was measured by nanoindentation. Using optical profilometry and spectral ellipsometry, the structural characteristics of a silicon carbide film on silicon were studied, namely, the film roughness and its thickness were calculated.

3D Structure Revealing of Thin Films by Means of Focal Series

The aberration corrected transmission electron microscopy era inspires the development of new research methods. Due to small aberration many of HRTEM applications have become more precise and reliable. The research presented in this paper is devoted to developing a new method for revealing the 3D structure of thin films by focal series processing. We have obtained the sum of the Fourie power spectra in the sliding window of focal series images. Relative defocus value for the minimum of the power spectra is a target function depending on the thin film roughness. For amorphous CoNiP alloy films the new method shows roughness of up to 8 nm for site 65*65 nm in X, Y planes.

Effect of Ionic Liquids on the Physical Properties of the Newly Synthesized Conducting Polymer

Conducting polymer has many applications in electronics, optical devices, sensors, and so on; however, there is still a massive scope of improvement in this area. Therefore, towards this aim, in this study, we synthesized a new thiophene-based conducting polymer, 2-heptadecyl-5-hexyl-6-(5-methylthiophen-2-yl)-4-(5-((E)-prop-1-enyl)thiophen-2-yl)-5H-pyrrolo[3,4-d]thiazole (HHMPT). Further, to increase its application, the interactions between the conducting polymer (HHMPT) and ionic liquids (ILs) were investigated by UV-Vis spectroscopy, FTIR spectroscopy, and confocal Raman spectroscopy techniques. Moreover, film roughness and conductivity of the polymer film with or without ILs were also studied. The imidazolium- and ammonium family ILs with the potential to interact with the newly synthesized conducting polymer were used. The results of the interaction studies revealed that the imidazolium family IL-polymer mixtures and ammonium family IL-polymer mixtures have almost similar conductivity at low concentration of ILs. This study provides an insight into the combined effect of a polymer and ILs and may generate many theoretical and experimental opportunities.