Search

Abstract Specific plasma engineering based synthesis can induce interesting photocatalytic antibacterial activities in TiO 2 films. This work presents the combination of pulsed DC (PDC) plasma with inductively coupled plasma (ICP) to synthesize undoped and nitrogen doped (N-doped) TiO 2 thin films using magnetron sputtering. The surface properties of resulting films were systematically analyzed in detail and correlated to the photocatalytic antibacterial activity against Gram negative Escherichia coli (E.coli). The addition of ICP source to PDC discharge generated TiO 2 films with enriched surface roughness due to the bombardment of highly activated species on the substrate. The ICP assisted films exhibited the morphology of nanoclusters with clear defined boundaries, higher O content and higher surface wettability. It was found that the films deposited with N-doping and addition of ICP source significantly increased the eradication of bacteria both in dark as well as in white light (artificial indoor light). Higher antibacterial activity of N-doped TiO 2 films in white light has been explained by photocatalytic degradation mechanism. Graphical abstract Image 1 Highlights • N-doped TiO 2 films have been deposited with tunable surface topography. • The surface topography and surface chemistry have been tailored through precise control of plasma species. • The high energy plasma produces the surfaces with higher wettability. • N-doped films with higher surface roughness exhibit significantly enhanced photocatalytic antibacterial activity. [ABSTRACT FROM AUTHOR]

Highly transparent, low resistive pure and Sb, Zn doped nanostructured SnO 2 thin films have been successfully prepared on glass substrates at 400° C by spray pyrolysis method. Structural, electrical and optical properties of pure and Sb, Zn doped SnO 2 thin films are studied in detail. Powder X-ray diffraction confirms the phase purity, increase in crystallinity, size of the grains (90–45 nm), polycrystalline nature and tetragonal rutile structure of thin films. The scanning electron microscopy reveals the continuous change in surface morphology of thin films and size of the grains decrease due to Sb, Zn doping in to SnO 2 . The optical transmission spectra of SnO 2 films as a function of wavelength confirm that the optical transmission increases with Sb, Zn doping remarkably. The optical band gap of undoped film is found to be 4.27 eV and decreases with Sb, Zn doping to 4.19 eV, 4.07 eV respectively. The results of electrical measurements indicate that the sheet resistance of the deposited films improves with Sb, Zn doping. The Hall measurements confirm that the films are degenerate n-type semiconductors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flexible transparent In/Ga co-doped ZnO (IGZO) thin films were achieved to fabrication on polyimide (PI) substrates by RF-magnetron sputtering method. • The microstructural evolution with annealing processing are enhanced the power factor to be achieved to 16.9 μW m−1 K−2. • Uni-leg thermoelectric thin film modules of four elements as fabricated were achieved the maximum power generation was found 3.2 nW at ΔT = 120 K. Transparent-flexible thermoelectric thin films have immense potential as power supplies for future small-sized consumer electronics, the internet of things, and wearable devices. Here, we report the thermoelectric properties of dual Ga and In doped ZnO films (IGZO) deposited on a polyimide substrate with post-thermal treatment in vacuum along with fabricating 4-unileg flexible IGZO thermoelectric devices. All the as-deposited and annealed IGZO films are the preferred (0 0 2) orientation and under tensile stress. The post-thermal treatment controls the dopant substitution/diffusion in the host ZnO lattice affecting the film crystallinity, residual stress, and thermoelectric properties. Among the films, the IGZO film annealed at 250 °C has the best power factor of 16.9 μWm−1K−2 with the largest crystal size, lowest tensile stress, highest carrier concentration, and lowest density-of-state effective mass. The practical application of flexible IGZO films was also reported via a 4-unileg-IGZO films thermoelectric module, which achieved an output power about 3.2 nW at ΔT = 120 K. [ABSTRACT FROM AUTHOR]

In this work, homogeneous Ag-doped Sb 2 Te 3 (AST) thin films were prepared using the rf magnetron sputtering technique. Thermoelectric properties of AST films have been investigated in terms of various substrate rotation speeds (20, 40, 60, and 80 rpm) and rapid post-thermal treatments at 250 oCin a vacuum. It was found that the thickness of AST films decreases with the increase in substrate rotation speeds. An Ag atomic composition slightly increases and the other Sb and Te atomic compositions slightly decrease with the increase of substrate speed rotations. The post-thermal treatment improved film crystallinity. Carrier scatterings at the grain boundaries tend to increase the resistivity and the Seebeck coefficient. The maximum power factor of 4.60 mW m−1K−2 (ρ = 19 μΩm, S = 298 μVK−1) is obtained in the AST thin films prepared with the substrate rotation speed of 60 rpm. The practical application of AST films was also reported via a thermoelectric module of five p -AST/n-Bi 2 Te 3 thin-film pairs with its achieved output power of 1.6 nW at ΔT = 20 K. • Ag–Sb–Te (AST) thin films were fabricated by RF magnetron sputtering. • Substrate rotation speed at 60 rpm induced highly homogeneous and more uniformity of thin films. • Rapid thermal annealing has changed amorphous to crystalline thin films as well as microstructure and thermoelectric properties enhancing. [ABSTRACT FROM AUTHOR]

Pure CdO nanostructured thin films and Ag doped with 1.0, 2.0 and 4.0 wt% doping concentrations were fabricated successfully on glass substrates with a cost-effective spin coating technique. The prepared films exhibit a cubic crystal structure oriented along (111) plane. The surface morphology of the pure CdO films shows a cauliflower shape structure, becomes granular, and compact at high Ag doping concentration. Raman spectra of the films reveal LO (longitudinal optical) and TO (transverse optical) vibration modes at 406.80 cm−1 and 566.54 cm−1. The absorption of the films significantly varies with Ag doping concentrations and as a result, the electronic structure of the films is tailored. Moreover, the optical band gaps vary in the range of 1.42–1.70 eV. In addition, the optical parameters n, k were studied in correlation with Ag doping concentrations. The obtained room temperature photoluminescence spectra of the prepared films show a broad peak at ∼350 nm. The third order nonlinear optical parameters of the films were also examined systematically. • Cauliflower morphology of pure CdO films was observed as incorporation of Ag films morphology change drastically. • Interesting change in NBE peak was observed as incorporation of Ag in CdO films. • 4.0 wt% Ag doped CdO films reveals remarkable enhancement in third order nonlinear optical susceptibility. [ABSTRACT FROM AUTHOR]