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The present study investigates the effect of precursor solution volume on the structural, morphological, compositional, optical, and electrical properties of In2S3 films. Thin films of In2S3 were deposited by a nebulizer spray pyrolysis technique on glass substrates with varying precursor solution volumes (4 mL, 8 mL, 12 mL, and 16 mL). X-ray diffraction studies confirmed the formation of the tetragonal phase and the compositional studies using energy-dispersive x-ray spectra showed the presence of only indium and sulfur. The energy bandgap of the films was found to be in the range of 2.51–2.4 eV. The I-V characteristics and photoresponses of the photodetectors including photosensitivity, responsivity, and detectivity were evaluated under visible light illumination. Enhanced photo-responsivity was observed with an increase in the precursor solution volume, with a maximum value of 0.213 AW−1 observed for the thin film coated with 12 mL precursor solution volume. For the thin film coated with a volume of 12 mL precursor solution, external quantum efficiency of 69% and detectivity of 20 × 109 Jones were observed. This In2S3 thin film may find application in the fabrication of efficient and cost-effective photodetector devices.

In this paper we demonstrate the use of atmospheric pressure plasma jet (APPJ) to functionalize the surface of hydrothermally synthesized vertically aligned TiO2 nanorods (TNRs) for photo electrochemical (PEC) application. The TNRs functionalized with the atmospheric pressure He-plasma showed relatively higher crystallinity, improved light absorption, and change in the morphology with additional surface area, leading to an enhanced photocurrent density than that of the untreated. Achieving the PEC performance on par with the best in the literature, this APPJ treatment is shown to be a promising technique to obtain better functionality with TNR kind of materials and many other nano-micro systems for various applications such as PEC hydrogen generation.

Metal chalcogenides have recently gained intensive attention due to their tunable bandgap energy, optoelectronic characteristics, and exceptional optical absorption. Because of the potential advantage of photodetectors, photovoltaic, holographic recording systems, and field-effect transistors, bismuth tri-sulfide (Bi2S3) crystals, in particular, have attracted a lot of focus in scientific research. In this study, the low-cost nebulizer spray technique was employed to synthesize the proposed Bi2S3:Sn thin films on glass substrates, varying the Sn doping concentrations in Bi2S3 films (from 1 to 3%). The crystallites of the orthorhombic-structured polycrystalline Bi2S3 films were all oriented in the same direction (130). According to the XRD spectra, preferred orientation and crystalline quality were improved by Sn doping concentrations up to 2%, but, above 2% of the Sn doping ratio, the structural properties were decreased. With increasing Sn-doping levels, the estimated direct band gap (Eg) of the Bi2S3:Sn films decreased, reaching a low value of 2.01 eV at 2% Sn and then rising. A field emission scanning electron microscope (FESEM) was applied to determine the size and shape of the grains in prepared Sn: Bi2S3 films.The 2% Sn-doped Bi2S3 thin film may be more appropriate for high-speed optoelectronic devices due to its high responsivity (1.24 AW−1), external quantum efficiency (40%), and detectivity properties (1.83 × 1010Jones). A potential mechanism for photodetector performance in the presence of air and UV radiation was also discussed in the present work for the proposed Sn: Bi2S3 thin films.

In the present work, zinc tungstate (ZnWO4) nanoparticles were synthesized by a simple co-precipitation technique without the addition of any templates and complexing agent. The X-ray diffraction study confirmed the formation of monoclinic structure ZnWO4. The annealing temperatures play a significant role on the crystallization of the samples and the crystallite size of ZnWO4 nanoparticles are varied between 30 and 65 nm. The well dispersed spherical solid shells along with nanoplatelet like morphology was obtained from the surface morphological study. The concomitant decrease in optical energy band gap value of ZnWO4 is due to the effect of crystallite size enhancement. It was observed that the crystallinity is one of the primary factors that affect the luminescence property of ZnWO4 nanoparticles. The purity and stoichiometric nature of synthesized product was confirmed by compositional analysis. The highest degradation efficiency of 87% was observed for 300 °C annealed ZnWO4 nanoparticles in the photocatalytic study by the degradation of methylene blue dye under ultraviolet light irradiation. The photocatalytic study confirmed the decomposition of methylene blue after 1 h irradiation.

Cadmium oxide (CdO) thin films doped with different yttrium (Y) concentrations have been prepared by the cost-effective spin coating technique. The effect of Y doping on structural, morphological, linear, and nonlinear optical properties of the as-prepared CdO thin films is studied. The AFM morphology of the thin films revealed grain size increase with the increase in the percentage of Y doping. From the optical properties, it is found that the films are highly transparent and the optical band gap spreads over the range of 2.3–2.8 eV. The Y doping drastically suppresses the linear and nonlinear optical properties.

This is paper briefly explains the MEMS based piezoelectrically actuated micropump and its applications for the drug delivery system. The micropump is designed and it consists of four elements like electrodes, piezoelectric layer, flexible membrane and a reservoir. It is analyzed for three different materials like PZT-5H, PZT-5A and BaTiO3. Among them BaTiO3 is used as piezoelectric material. By using the FEM tool COMSOL Multiphysics, mechanical behavior of the micropump is evaluated as flow velocity and flow rate of 8.92 m/s and 0.854 ml/min at 50 V respectively. The obtained flow rate for the micropump is best suitable in cardio-vascular, hypertension cases where the drug need to be delivered with an appropriate flow rate.

The Cu-doped ZnO thin films were fabricated on glass slides by a two-step SILAR coating method. The diffraction data revealed that the prepared ZnO:Cu films were in the phase of Wurtzite geometry, and the grain size decreases from 37 to 26 nm. The morphological studies revealed uniform distribution of nanograins as well as a nanoflower structure. The doping samples exhibited an increase in transmittance and an increase in the bandgap. A room temperature ammonia vapor-sensing performance of Cu-doped ZnO films is also studied, and sensitivity for sensing ammonia vapor is increased with doping concentration. The sensitivity was remarkably enhanced to 12,300% and it has a relatively fast response/recovery time of 37/8 s for 100 ppm NH3 for the 5 wt% of ZnO:Cu film. Its high sensitivity and fast response make the ZnO:Cu film a good contender for high-quality gas sensor devices.

This paper reports successful fabrication of copper-doped tin sulphide (SnS:Cu) thin films using nebulized spray pyrolysis. Different Cu doping concentrations (2, 4, 6, and 8 wt-%) were employed to...

Currently several type of energy sources exist in the modern world. The energy makes people's life more comfortable, easy, time savings, fast transformation of information and various modes of transmission. Because of large demand of energy, efforts on production of energy increases day by day which subsequently increase serious environmental concerns such as pollution and lack of existing natural resources. In this respect, several attempts have been proposed for new type of renewable and chemical energy systems to overcome the economic burden, global warming and environmental problems caused by the use of conventional fossil fuels. Hydrogen production via water splitting is a promising and ideal route for renewable energy using the most abundant resources of solar light and water. Cost effective photocatalyst for Photoelectrochemical (PEC) water splitting using semiconductor materials as light absorbers have been extensively studied due to their stability and simplicity. Over the past few decades, various metal oxide photocatalysts for water splitting have been developed and their photocatalytic application was studied under UV irradiation. Alternative semiconductor photocatalyst should harness solar energy in the visible light, one such semiconductor material is indium gallium nitride (InGaN), owing to its suitable and tunable energy band-gap, chemical resistance and notable photoelectrocatalytic activity. This review article is initiated with the brief introduction about the origin and methods of production of hydrogen gas from both renewable and nonrenewable energy sources. Multi-functional properties and applications of InGaN are described along with past and recent efforts of InGaN materials for hydrogen evolution by several investigators are provided in detail. In addition, future prospects and ways to improve the PEC performance of InGaN are presented at the end of this review.

Carbon (C)-coated zinc oxide (ZnO) nanoparticles (NPs) having different sizes and morphologies were successfully synthesized by a flash combustion biomimetic approach using different contents of gelatin as the medium. Structural and vibrational studies indicate that the NPs are grown in a hexagonal wurtzite structure. The amount of gelatin content has a strong effect on the growth mechanism and the physical and optical properties. The presence of C in the ZnO was clearly confirmed by Raman analysis in which the Raman bands corresponding to the presence of C were observed at ∼ 1343 cm−1 (G-band), 1580 cm−1 (D-band), and 2700 cm−1 (G′-band). At low concentrations, the NPs grew in the shape of spherical aggregates which arranged themselves in the form of a spherical flower-like structure. At 1 g of gelatin content, the spherical flower-like structure disappeared to be distributed at 3 g of gelatin content into a uniform planar spherical NP arrangement in the shape of a multi-aggregated cauliflower-like structure. At higher concentrations, the NPs rearranged themselves in the shape of a hexagonal disk or a prism-like structure. The band gap values were found to decrease with increasing gelatin content and were in the range of 3.18–3.26 eV, though it showed the dependency on the size, shape and presence of C in ZnO. Studies of the dielectric properties and ac conductivity on the prepared NPs were also carried out.

In this study, solvothermal method was used for the synthesis of MnFe₂O₄ nanoparticles at different processing period of 7, 14, and 21 h. X-ray diffraction (XRD) pattern study confirms that MnFe₂O₄ nanoparticles correspond to the face-centered cubic spinel structure and belong to the Fd3m [227] space group. From Raman spectra analysis, two major peaks were observed at 476 and 616 cm-1, which correspond to the vibration modes of MnFe₂O₄ nanoparticles; especially, the broad peak at 620 cm-1 (A1g) corresponds to the symmetric stretching vibration of oxygen atoms at tetrahedral site. Infrared spectra (FTIR) analysis at 490 and 572 cm-1 can be attributed to the stretching vibration of tetrahedral groups of FeO₄, and the vibration of octahedral groups of FeO6 belongs to the intrinsic vibrations of manganese ferrites. The uniformly distributed MnFe₂O₄ nanospheres (RT2) can be affirmed by field emission scanning electron microscopy images and confirmed by the high-resolution transmission electron microscopic studies. The electrochemical properties of synthesized MnFe₂O₄ nanoparticles investigated by cyclic voltammetry, impedance spectroscopy and galvanstatic charging and discharging (GCD) studies clearly predict the reversible faradaic reactions of MnFe₂O₄ nanospheres. Further, the MnFe₂O₄ nanospheres (RT2) exhibit high specific capacitance of 697 F g-1 at 0.5 A g-1 current density in galvanostatic charging and discharging profile and after 1000 cycles exhibits 79% retain ability of initial specific capacitance and hence can be considered as the efficient electrode for supercapacitor applications.

We report co-doping effects of transition metal elements (Ni, Co) primarily on the opto-electronic properties of CuO thin films. CuO, CuO:Ni(1%), CuO:Co(1%) and CuO:Ni(1%):Co(1%) thin films were deposited via the spray pyrolysis route. Structural studies revealed the monoclinic CuO structure for all films. For all the films scanning electron microscope (SEM) images showed a crack-free and homogeneous surface. Photoluminescence (PL) spectra of all the films exhibited four emission peaks at 415, 451, 477, and 521 nm wavelengths. The optical bandgap (E g) values were around 2.12 eV, 2.18 eV, 2.05 eV and 1.84 eV for CuO, CuO:Ni(1%), CuO:Co(1%) and CuO:Ni(1%):Co(1%)thin films, respectively. CuO:Ni(1%):Co(1%) photo-device displayed a large responsivity (R) of 0.43 AW−1, external quantum efficiency (EQE) of 100% and detectivity (D *) of 9.55 × 109 Jones. Hence, co-doping of transition metal elements would be one of the effective approaches for enhancing opto-electronic properties of metal oxide compounds.

A transparent flexible polymer film is chemically functionalised with a bent-core liquid crystal (BCLC) compound for effective alignment of the bulk BCLC sample at the substrate–LC interface. The surface attachment was achieved via a simple procedure which involved pre-treatment of the polymer film (commercial name: over head projector film) using piranha solution followed by chemically attaching the BCLC compound through silane condensation reaction. Surface characterisation of the unmodified and BC-modified flexible films was carried out through X-ray photoelectron spectroscopy (XPS), attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy, contact angle (CA) and atomic force microscopy (AFM) techniques. The BC-modified flexible substrates are analysed for their efficiency to orient the bulk LC sample. Remarkably, the chemically modified polymer substrates are highly efficient in vertically aligning both the BC and rod-like LC samples at the substrate–LC interface, in comparison to their unmodified counterparts. The described method is simple, reproducible, surface modified substrates are highly stable and more importantly reusable. The demonstrated method for the alignment of BCLCs advances a step forward towards the realisation of applications proposed for these fascinating compounds.

The photoelectrical splitting of water is an important technique for the efficient generation of hydrogen using catalysts. However, understanding the effects of the size and crystallinity of catalysts is essential for tuning the efficiency of photo electrochemical hydrogen production. In this study, we synthesized WO3 nanocubes with controlled uniform size and shape using a low-temperature hydrothermal method at various temperatures. The nanocubes obtained at a calcinations temperature of 450 °C exhibited higher crystallinity and superior photo catalytic performance during the photo electrochemical production of hydrogen via the oxidation of water in KOH solution. The band gap was determined as ∼2.54 eV with a photocurrent density of 0.0021 mA/cm2 and a flat band potential around −0.77 V. The nanocubes also exhibited good stability in the alkaline KOH electrolyte for 2 h. Therefore, the superior crystallinity of the WO3 nanocubes could enhance the density of the charge carriers and improve the stability while also decreasing the band gap. These findings may facilitate the fabrication of a stable photo anode for large scale water splitting applications.

Neodymium doped zinc sulphide (Nd: ZnS) thin films were coated on glass substrates at 450 °C through low cost nebulizer spray pyrolysis (NSP) method. Structure, morphology, opto-electrical characteristics of Nd doped ZnS films with various Nd doping concentrations (0%, 1, %, 3% and 5%) were studied. X-ray diffraction patterns revealed that all coated films were polycrystalline hexagonal structure with (102) as a preferential direction. SEM images showed smooth and uniform spherical grains without any cracks and pinholes. Topological view by AFM described the increasing of roughness of the film through doping concentration. EDAX and Elemental mapping images confirmed the presence of Zn, S and Nd without any other impurities. Raman spectra reveals that E1(LO), 2TO, 2LO and 3LO emission modes with corresponding to the wave number. PL spectra showed high intense visible and broad UV emission band at 463 nm and 397 nm, respectively. Thickness of the films increased with Nd doping concentration reflecting the reduction of transparency of the films from 86% to 78% for 0% and 5% of Nd. UV–Vis Spectrum was used to study the energy gap (Eg), dielectric constant(e), refractive index(n), and extinction coefficient (k) of the prepared films. Four-point probe method was used to calculate the activation energy of Nd: ZnS thin films from the graph drawn between ln (ρ) and (1/T).

Er-doped CdO thin films are coated on FTO substrates using so-gel-spin coater technique. XRD studies confirm the polycrystalline nature of (111) orientation of the films. Crystallite size, dislocation density, and Lattice strain is calculated from XRD data and found that they are varying with doping percentage. AFM studies revealed homogeneous distributions of the nano-grains of 13–19 nm size. Energy dispersive spectroscopy and mapping analyses confirm the elemental composition. All the films are showing high transmission of nearly 80% in the visible spectrum. The calculated direct, indirect band gap values are changing with a variation of doping from 2.85 to 2.97 eV. At higher wavelength, the dielectric constant values are in the range of 20–80. The linear, third-order susceptibilities and nonlinear refractive index values are varying from 2 to 7, 1.6 × 10−13 to 5.41 × 10−13 esu and 1.39 × 10−12 to 8.1 × 10−11 esu respectively.

Nebulizer assisted spray technique has been implemented for the deposition of pure and gadolinium (Gd) doped PbS thin films at a substrate temperature of 210 °C onto glass substrate using lead nitrate and gadolinium (III) acetate as precursors. Doping percentage of Gd was varied from 0 to 5 wt% for the preparation of Gd doped films and to analyze the film property. A variety of techniques like X-ray diffraction, Raman spectrum, scanning electron microscopy, atomic force microscopy, energy dispersive X- ray, UV–Visible spectrometer, and keithley source meter were used to study the influence of Gd doping in PbS thin films X-ray diffraction revealed no change in preferential orientation of the crystal planes without any secondary phases formed for all the Gd-doped films. And also it confirmed that the nature of the films were polycrystalline with simple cubic structure. It also further confirmed polycrystalline simple cubic structure with decrease of crystallite size from 21 nm to 16 nm for the increase of gadolinium doping concentration from 0 to 5 wt%. Noticeable change in the grain size was observed for the 5 wt% of gadolinium doping with uniformly distributed spherical shaped nanosize grains fully covering the entire surface. The compositional analysis confirmed the presence of Pb, S and Gd in the films. The optical parameters of Gd doped PbS thin films such as band gap energy, refractive index; extinction co-efficient, and real and imaginary parts of dielectric constant were determined using transmission, absorption and reflectance spectra in the range of 300–2400 nm. A maximum value of photo current was observed for 5 wt% gadolinium doped film.

Quercetin is well known for its effective inhibition of cancer cell proliferation by inducing the apoptosis. In the present study, quercetin isolated from Allium cepa were loaded on a biodegradable polymer, poly(lactic-co-glycolic acid) (PLGA) microspheres and its apoptotic potential in Michigan Cancer Foundation (MCF-7) cell was investigated. PLGA microspheres before and after loading indicated no significant difference in size as the average size of the microspheres were 100 μm. The encapsulation efficiency of quercetin on PLGA was found to be 74 ± 1.2%. Cytotoxicity and flow cytometric analysis were used to evaluate the capacity of quercetin-PLGA microspheres (PLGAq) on anticancer activity. PLGAq were assessed at two different concentrations (1.5 μg and 3.0 μg) and indicated that at higher concentrations it showed effective inhibition of cancer cells. The results indicated that the PLGAq microspheres efficiently inhibit cell proliferation by inducing the apoptosis demonstrating that the biodegradable PLGAq microspheres will provide a promising therapeutic approach for the treatment of breast cancer.

Economic nebulizer spray pyrolysis (NSP) technique has been employed to deposit Neodymium (Nd) doped Tin disulfide (SnS2) thin films at 325 °C by varying the doping concentration of Nd (0%, 2%, 4% and 6%). The impact of Nd concentration on crystalline structure, morphology and opto-electronic properties of films were studied using X-ray diffraction (XRD), FT-Raman spectrophotometer, atomic force microscope (AFM), energy-dispersive X-ray spectroscope, scanning electron microscope (SEM), UV–Visible spectrometer and Hall Effect measurements. Structural parameters such as lattice constants, texture orientation factor, micro strain, dislocation density and crystallite size were estimated using XRD data. The SEM and AFM images of films displayed an exceptional morphology. The surface roughness of the films was found to increase with the increase of dopant concentration. Optical analysis done on the films revealed variation in band gap from 2.75 to 2.92 eV as the Nd doping concentration is increased from 2 to 6%. SnS2 thin film exhibited n-type conductivity as, confirmed from Hall Effect studies. The resistivity and concentration of the carrier in the film were found to be 4.17 × 10−2 Ω cm and 4.06 × 1017 cm−3 respectively which were then correlated to the deposition parameters. Furthermore, FTO/n-Nd-SnS2/p-SnS hetero-junction based solar cells were prepared and their current voltage curve in dark condition was obtained.

In the current work, the authors studied a hybrid organic-inorganic photodiode combining n-type monocrystalline silicon (n-Si) and indigo dye where the natural dye indigo has been applied as an interfacial layer between Gold (Au) and n-Si. The electrical and photo-response characteristics of photodiode based on indigo dye were investigated through current, conductance and capacitance studies measured under the wide illumination intensity and frequency ranges. The frequency dependency of capacitance-voltage (C-V) and conductance-voltage (G-V) characteristic properties of the Au/Indigo/n-Si photodiode was examined in the frequencies varying from 100 kHz to 1 MHz in view of the effects of series resistance (Rs), the concentration of donor atoms (Nd) and density of interface states (Nss). The C-V and G -V studies indicate that the Nss and Rs are key factors which are strongly influencing the electrical properties of the fabricated Photodiode. From the obtained results, the fabricated Au/Indigo/n-Si photodiode can be a promising contender for electro-optic device engineering.

The SnO2 nanoparticles formation by hydrothermal method at different experimental conditions such as temperature, pH, reaction time, and capping agent (cetyltrimethylammonium bromide), was studied. X-ray diffraction results confirmed regular rutile crystal structure of SnO2. The characteristic Raman peak observed at 635 cm−1 corresponded to A1g modes of Sn–O vibrations. The study of optical property using photoluminescence confirmed the emissive spectra of SnO2. The infrared peak observed at 618 cm−1 corresponded to Eu modes of Sn–O vibrations of TO phonon because of E⊥ to c-axis. Scanning electron microscope images clearly revealed the formation of complete SnO2 nanoparticles. The unique SnO2 nanoparticles stacked together to form microspheres at pH-5 showed high specific capacitance of 274.8 F/g at a current density of 0.5 A/g. The observed results confirmed the feasibility of SnO2 nanoparticles being used as appropriate positive electrode candidate for supercapacitor applications.

In this study, Fe-, Ce-, and La-doped TiO2 ultrafine nanospheres were synthesized via low-temperature solvothermal method. The structural and morphological variations of bare and M (Fe, Ce, La)- doped TiO2 were confirmed by X-ray photoelectron spectroscopy and transmission electron microscopy images. The fabricated photoanodes were tested using 1 M KOH electrolyte and demonstrated that they can be used for eco-friendly photoelectrochemical solar water-splitting application. Compared to bare TiO2 photoanodes, foreign cations (Fe, Ce, La)-doped TiO2-based photoanodes exhibited higher photocurrent response without bias. In nutshell, the rare-earth element La-doped TiO2 nanosphere photoanode showed good photocurrent response to approximately 0.48 mA/cm2 under illumination, with lower flat band potential shift of −0.83 V. The highest photostability of 96% was achieved over 2 h for 10% La-doped TiO2 nanosphere photoanode and was suitable for solar water-splitting applications.

Transparent conductive oxides (TCOs) are having emerging applications in optoelectronic technology. Hence, herein, we have designed and fabricated the cadmium oxide (CdO/FTO) TCO films with different concentrations of Lanthanum (La) through a facile spin coating technique. The crystal system and phase confirmation of fabricated films was analyzed by X-ray diffraction analysis. The values of D 200 are found in the range of 25–31 nm indicates nanostructured thin films fabrication. EDX/SEM mapping revealed the presence of La and its homogeneity in CdO film. Atomic force microscopy was carried out to investigate the effect of La doping on surface topography of CdO films. The average values of grain size were estimated in the range of 7.56–10.95 nm along with surface roughness in range of 15.25–17.56 for pure and La-doped CdO films. The optical transparency of films was noticed in range of 75–85% in the NIR region. Direct and indirect band gap values are found in the range of 2.55–2.8 eV and 2.0–2.4 eV, respectively. The dielectric constant, loss, refractive and absorption indices were also calculated. Moreover, the linear, nonlinear susceptibilities and refractive index values were estimated and found in the range of 0.1–3, 1 × 10−12 to 1.6 × 10−7 esu and 2 × 10−12 to 1.28 × 10−8 esu, correspondingly.

NiO has been found to have excellent physical properties which are crucial for several significant electro-optical devices. Herein, we have designed and fabricated high-quality films of NiO with various concentrations of Ce and studied their key properties. X-ray diffraction (XRD) study confirmed the cubic phase, good crystallinity and growth direction along (111) plane in the prepared samples. The crystallite size was noticed in the range of 13–30 nm. For confirming the presence of Ce doping and its homogeneity in NiO films the EDX/SEM mapping was carried out. AFM study provided the topographic information in terms of size of the grains and roughness of all films. The grown films were found to be 70–80% optically transparent in the whole testing region. Optical energy gap was found to expand from 3.60 to 3.68 eV owing to Ce-doping. The refractive index value was noticed to be in the range from 1.7 to 2.7. The n2 and χ ( 3 ) values for pure and Ce-doped NiO films varied from 2 × 10−10 to 1.4 × 10−11 and 1 × 10−12 to 1.1 × 10−11 esu, respectively. Obtained results indicated that Ce has strong influence on opto-nonlinear characteristics of NiO films and proposed their application in the opto-nonlinear devices.

In the present work, pure and magnesium doped Cu2O films were deposited on glass substrates by nebulizer spray pyrolysis method with doping concentrations of 0, 3, 5 and 7% at 280 °C. The as-prepared films were analyzed by XRD, AFM, laser Raman, UV–Vis, photoluminescence, Hall Effect measurements. An X-ray diffraction study clearly depicts that films are possessing polycrystalline nature with a cubic structure. The surface topological properties have been characterized using atomic force microscopy (AFM) which reveals nano shaped hill rock grains covered the surface of the substrate. Laser Raman spectroscopy studies confirm the peaks observed at 109, 148, 217, 416 and 514 cm−1 belong to Cu2O phase. UV–Vis spectrophotometer measurements show that the band gap is decreased from 2.25 to 1.9 eV for the increase of doping concentration Mg. Photoluminescence spectral analysis giving an emission peak at 630 nm confirmed the formation of cuprous oxide. The electrical studies showed that the films are of p-type. For the doping of 7% Mg concentration the Cu2O showed a resistivity 1.53 × 102 andhigh carrier concentration of 21.67 × 1016 cm−3. FTO/ZnO/Cu2O/Ag heterojunction was fabricated using 7% Mg doped Cu2O thin film, and found the open circuit voltage (Voc) as 0.25 V, short circuit current (Isc) as 0.225 × 10−4 A and the efficiency as 0.65% for the 7% Mg doped Cu2O thin film.

Synthesis of polyoxometalates (Cu3Mo2O9 nanopowders) was obtained by using solvothermal method and confirmed by X-ray diffraction pattern, with orthorhombic crystalline structure belonging to the space group Pna21(33). Further, the synthesized Cu3Mo2O9 nanopowders were analyzed by using Raman, infrared, and photoluminescence studies. X-ray photoelectron spectroscopy study explained the oxidation states of Mo-3d, Cu-2p, and O-1s in Cu3Mo2O9 nanopowders. Field emission scanning electron microscopy images clearly revealed the formation of nanostructure randomly oriented to form an interconnected rout, which emerged as a good candidate for storing more charges at the surface of Cu3Mo2O9 nanopowders. The electrochemical studies, such as cyclic voltammetry, electro impedance analysis, and galvanostatic charging–discharging studies, were used to analyze its electrochemical properties. To ensure the stability of Cu3Mo2O9 nanopowders, continuous charging and discharging studies were conducted for 1000 cycles at a current density of 5 A g−1 and it exhibited good stability over a large number of cyclic studies with capacity retention of 99.2% after the first 500 cycles.

Sol–gel spin coating is applied to fabricate the pure and different concentrations of aluminum (Al)-doped ZnO films on high-quality silicon substrates. All films are showing high crystallinity in X-ray diffraction study, and lattice constants were obtained using PowderX software. The value of crystallite size was found in range of 20–40 nm. EDX/SEM mapping was performed for 2 wt% Al-doped ZnO film, which shows the presence of Al and its homogeneous distribution in the film. SEM investigation shows nanorods morphology all over the surface of films, and the dimension of nanorods is found to increase with Al doping. The E(g)dire. values were estimate in range of 3.25–3.29 eV for all films. Linear refractive index was found in range of 1.5–2.75. The χ1 value is found in range of 0.13–1.4 for all films. The χ3 values are found in range of 0.0053 × 10−10 to 6.24 × 10−10 esu for pure and doped films. The n2 values were also estimated. These studies clearly showed that the properties of ZnO have been enriched by Al doping, and hence doped films are more appropriate for optoelectronic applications.

In this work, nanostructured methyl violet-10B (MV-10B) thin films of various thicknesses were coated on glass substrates by a low-cost spin coating method at different rpm. The structural analysis of nanostructured MV-10B thin films was carried out by X-ray diffraction and atomic force microscope. Optical measurements were carried out, and the direct band gap of MV-10B films was estimated. The study showed that the prepared MV-10B thin films act in the same manner as that of conventional direct bandgap semiconductors. From optical studies, the sample exhibited bandpass filter characteristics in IR range from 700 nm to 900 nm and in the visible range centered around 408 nm. Also, the sample absorbs or attenuates the range of wavelengths in the visible spectrum between 470 and 650 nm creating a good absorption band valley making a CUT-OFF laser filter. Optical constants such as refractive index (n) and extinction coefficient (k) were computed using Kramers–Kronig relations. The real and imaginary components of dielectric constant were calculated on the basis of polarization of light when it is impinging on semiconductors. Nonlinear index of refraction and susceptibilities were estimated by linear refractive index dispersion principles. Optical limiting studies showed that the MV-10B thin films are very good optical limiters even at low thickness. The MV-10B showed a laser attenuation behavior for He-Ne and green lasers. The obtained results suggest that the newly designed thin films are the promising candidate in different applications.

Herein, we report samarium (Sm) dopant concentration effect on Cu2O films characteristics prepared by electrodeposition method. XRD patterns of the films indicated that pristine and Sm:Cu2O films have polycrystalline cubic structure with (111) preferred orientation. It was seen from the SEM photographs pinhole free dense triangle shaped grains for undoped Cu2O thin films and the grain size was decreased as concentration of samarium was increased. Raman spectroscopy showed peaks at 108, 146, 217, 413 and 637 cm−1 which conformed the Cu2O phase formation and intensity of the peaks was decreased with a increase in dopant concentration. UV–Vis spectra exhibited that the absorption value of Cu2O films is increased gradually with reduction in band gap value for the increase of samarium content. Photoluminescence (PL) spectra revealed that all films display a visible light emissions and its intensity was reduced due to increase in doping concentration. Photosensitivity observation study indicated that the photocurrent of deposited Cu2O films was increased along with the increase in dopant material concentration.

Pure and Ag doped CdS nanocrystalline films with different Ag doping concentrations were successfully grown on glass substrates by a sol-gel spin coating method. Ag doping was performed using silver acetate aqueous solution with 0.01, 0.02 and 0.03 M concentrations via ion exchange. The influences of Ag doping on structural, vibrational, morphological, linear and third order nonlinear optical properties of CdS nanocrystalline films were studied. The x-ray diffraction patterns of the films exhibited a broad peak centered at an angle 2θ = 26.5° along the (111) plane, which confirms the cubic structure and formation of nanocrystalline films. Raman spectra of films demonstrate a shift in longitudinal optical phonon vibrations as compared to the bulk counterpart. Pure CdS film shows high transmittance (83%) in the visible and near infrared (NIR) regions. With Ag doping, a significant red shift in the band edge and reduction in the transmittance of the films in visible and NIR regions were observed. However, the films doped with Ag showed appreciable transmittance in visible region for window layer applications. A significant effect on optical parameters such as absorption index, refractive index, and optical dielectric constant was observed after Ag doping. The nonlinear optical properties of films were enhanced with incorporation of Ag atoms into the CdS binary system. The values of nonlinear optical susceptibility χ(3) and refractive index n2 were found to increase with increasing Ag concentration and were estimated to be in the range of 2.92 × 10−10 − 1×10−7esu and 1.00 × 10−9 − 2.00 × 10−7esu, respectively. These values suggest that these films can be potential candidates for nonlinear optical device applications.

In this study, we investigated the monocrystal growth and characteristics of pure and methyl violet (MV) dyed zinc(tris) thiourea sulfate (ZTS) large size single crystals. The morphology of ZTS was modified in the presence of MV dye. The crystals were crushed for a finite time to obtain powders for X-ray diffraction analysis and the lattice parameters were determined. The crystals were analyzed based on Fourier transform-Raman spectroscopy measurements and the vibrational modes were identified. Some extra vibrational modes were observed due to the presence of the MV dye. Ultraviolet–visible–near infrared optical absorbance measurements were recorded and the band gap was calculated. A large band gap ∼4.31 eV was obtained for the ZTS crystals, which supports their possible application in electro-optic devices. Two absorption bands at around 584 nm (sharp) and ∼362 nm (broad) were also observed in the dyed crystals but not in the pure crystals, thereby indicating the interaction between the dye and ZTS. Photoluminescence (PL) emission studies were conducted at an excitation wavelength of 360 nm. PL emission peaks were observed at ∼433 nm in the pure crystals, and at ∼421 and 444 ± 5 nm in the dyed crystals. Differential scanning calorimetry demonstrated the increased melting temperature of ZTS in the presence of the dye. The dielectric constant, ac electrical conductivity, and mechanical strength were higher for the dyed crystals. Our results suggest that the dyed crystals may be more suitable for applications in opto-electronic devices compared with the pure crystals.

The present work deals with the deposition of NiO and Nitrogen (N)-doped NiO thin films by sol-gel spin coating technique. Structural, morphological, linear and non-linear optical characteristics of undoped and N-doped (1–15 wt%) NiO films were studied. From XRD measurements, it is evident that single phase nano crystalline NiO is formed for all doping concentrations. Surface morphology study shows that higher concentration of N doped NiO thin films were of high quality and EDX mapping confirmed the doping of Nitrogen in films. The Raman spectra of the studied films were analyzed over the range of 1400-200 cm−1. The optical studies confirm that as doping increases, transparency of the film decreases (except at 10% N doping) and the band gap narrows. Nonlinear parameters such as refractive index and susceptibilities also depend on N dopant concentration. Z-scan studies viz., absorption index, nonlinear refractive index were carried out on undoped and N doped NiO samples and the results were matched with theoretical calculated values.

The undoped and terbium (Tb)-doped SnO2 thin films are coated on the glass substrates using the nebulized spray pyrolysis (NSP) technique. The crystallite size is calculated using the Williamson-Hall method and is found to be decreased from 80 to 56 nm with the increase of Tb doping concentration. Atomic force microscope (AFM) images show the spheroidal shape of the grains. The elemental analysis of the samples was investigated by energy dispersive analysis of X-rays (EDX). An increase in absorbance and decrease in bandgap values provide more photon absorption which enhances the photocatalytic reaction. The PL studies reveal the creation of more defect levels by doping which provides more active sites for catalyzed reactions. The Tb doping with SnO2 improved the rate constant about 0.015/min, and a maximum photocatalytic dye degradation efficiency of 85% against methylene blue dye was observed. Therefore, the fabricated films found potential applications for photocatalysis that enable them to chemical industries.

Cadmium sulphide (CdS) thin films are widely used for various devices applications. Here, we report on the development of nanostructured CdS and Na-CdS thin films with enhanced optical and emission properties using an inexpensive deposition method. High quality Na-CdS nanocrystalline films were fabricated using spin coating method on glass substrates with different doping concentration (1–4 wt%). X-ray diffraction studies of the prepared films reveal a cubic zinc blende structure. The crystallites sizes of the films were found to be about ~ 5–11 nm and significantly increase with increasing Na doping concentrations. Morphological imaging of the grown films shows spherical nano-size grains in the range of 9–27 nm. The nanocrystalline films show high transmittance (~ 85%) in the visible region and was found to increase with increasing Na doping content. Room temperature photoluminescence (RTPL) spectra of the films reveal a direct band to band transition with enormous amount of enhancement in near band emission (NBE) up to 400% for the films doped with 1 and 2 wt% Na concentrations which is about ten times higher as compared with pure CdS films. A good improvement was also observed with Na doping in the linear and third order nonlinear optical properties of the films. The reported results in the current study show the high potential of Na-doped CdS films as candidates for low cost high performance optoelectronic devices.

An azobenzene derivative containing a dimethylchlorosilane end group was chemically attached to a flexible polymer substrate to create permanent photo alignment layer. The commercially obtained polymer substrate (overhead projector film) was characterised and found to contain cellulose acetate as the main component. Surface functionalization of the substrate was confirmed through X-ray photoelectron spectroscopy (XPS), attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy, water contact angle (CA) and atomic force microscopy (AFM) techniques. Photo-isomerisation behaviour of the azo-layer on the polymer substrate was additionally confirmed by UV-diffuse reflection spectroscopy (UV-DRS). Further, the azo-modified flexible substrate was analysed for the orientation of the bulk liquid crystal (LC) sample and tuning the LC orientation by utilising photo-switching behaviour of the azo-layer on the substrate.

This work reports on structural, electrical, optical, and photosensing properties of La and Zn co-doped CdO thin films. The co-doped CdO thin films were prepared on glass slides using the nebulizer spray method at 400 °C. From the structural analysis, a decrease in the crystallite size from 17 to 14 nm is observed against the incorporation of La in CdO:Zn. Inclusion of La in CdO:Zn has also changed the surface morphology with a reduction in the roughness of the thin film samples. EDX analysis confirmed the incorporation of La with CdO: Zn in the prepared films. The bandgap value of the prepared samples increases with the rise in La dopant concentration. A 1.5 wt% of La co-doped with CdO:Zn thin film sample produces low resistivity of 0.68 Ωcm and a better figure of merit of 8.4 × 10 −4 Ω-1. Finally, the fabricated photodetector with 1.5 wt% of La co-doped with CdO:Zn thin film shows a higher photocurrent and an ideality factor value of 3.4. The photosensing properties of the fabricated (p-Si/CdO–Zn–La (1.5%)) photodetector shows a higher responsivity (R) value of 1.18 AW-1, specific detectivity (D*) value of 4.90 × 109 Jones, and external quantum efficiency (EQE) value of 274% with 3.0 mW/cm2 light intensity. The switching characteristics of the photodetector show a faster rise time (2.9s) and fall time (3.6s) suggesting the fabricated device is also suitable for photosensing applications.

In this study, for the first time, rare earth element gadolinium and aluminum co-doped zinc oxide (Gd:AZO) films were prepared on insulating glass plates using cost-effective nebulizer spray method with various Gd co-doping levels (0, 0.5, 1 and 1.5 at.%). The deposited films were characterized using X-ray diffraction, FT-Raman, AFM, EDAX, UV-VIS spectroscopy, Photoluminescence (PL) spectrum and Hall Effect measurement at room temperature. From XRD study, it is confirmed that the Gd and Al ions are incorporated into ZnO lattice. Film crystallinity is slightly reduced due to Gd content by increasing lattice defects. Topology of AFM images displays a slight increase of Gd:AZO thin film roughness from 20 nm to 36 nm, with an increase of thickness from 232 to 324 nm respectively. Elemental mapping and EDAX studies confirmed the existence of Zn, O, Al and Gd elements in the prepared Gd:AZO thin films. Spray deposited pristine AZO films showed maximum optical transmittance ∼91% in entire wavelength spectrum and energy gap value ∼3.31eV. The observed PL spectra showed as a UV emission at 387 nm for deposited films. The obtained minimum resistivity and maximum figure of merit values are 3.42 × 10−4 Ωcm, and 18.68 × 10−3(Ω/sq)−1, respectively for 1.5 at.% Gd co-doped AZO thin film. Both values are decent enough for opto-electronic devices.