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In this article, Nickel doped rutile structure tin oxide (SnO₂) nanoparticles have been prepared by simple chemical co-precipitation method and prepared samples were characterized by Powder X-ray Diffraction, Fourier transform infrared Spectroscopy, Microraman analysis, Photoluminescene Spectroscopy, UV-Visible Spectroscopy, Energy dispersive analysis and Field emission scanning electron microscope. XRD studies revealed the single phase tetragonal rutile structure with space group of P42/mnm. The average crystallite size of the particles was decreased from 27 to 22 nm with increasing Ni doping concentration. FTIR spectra confirmed the presence of various bands such as O-H, C-H, Sn-O-Sn. Raman modes Eg, A1g and B2g were assigned at 478, 630 and 740 cm-1 which confirmed the single phase of pure and Ni doped SnO₂ nanoparticles. The photoluminescence spectra confirmed that the defect related emissions increased with increasing of Ni concentration. The UV absorption spectra showed that the absorption of the particles decreased with increasing Ni concentration and the band gap values decreased from 3.7 to 3.4 eV. EDX spectra confirmed the presence of Sn, Ni, O in pure and doped samples. The photocatalytic activity of the pure and Ni doped SnO₂ nanoparticles were analyzed by using methylene blue dye under visible light irradiation. It is concluded Ni (7%) doped SnO₂ nanoparticles have higher degradation efficiency compared to pure SnO₂ nanoparticles.

Pure and rare earth elements of samarium (Sm), lanthanum (La) and neodymium (Nd) doped cadmium oxide (CdO) thin films were deposited on glass substrates by radiofrequency magnetron sputtering at room temperature. The influence of rare earth dopants on the microstructural, morphological and optoelectronic properties of the CdO thin films were studied elaborately. The X-ray diffraction studies revealed the polycrystalline with face centered cubic structure of CdO thin films. The structural defects were increased with increase of dopant’s ionic radii. The presence of the dopants in host CdO thin films was confirmed by X-ray photoelectron spectroscopic analysis. The roughness of the films was decreased for the doped samples and Nd doped CdO thin film has the minimum roughness value of 1.29 nm. All the films exhibited high transmittance in visible range and well pronounced Moss-Burstein shift was observed in the band gap value. Emission bands of photoluminescence spectra depicted the presence of oxygen vacancies. Hall Effect measurement showed an increase in carrier concentration and electrical conductivity of the films with the addition of dopants. The suitable combination of high conductivity (2872 Ω−1·cm−1) with optical transparency (88%) and lower surface roughness of Nd doped CdO thin film, makes it a potential candidate for the transparent conducting oxide in optoelectronic devices.

The peculiar morphology of nanorods mixed with microspheres of manganese carbonate (MnCO3) doping with different percentages (0, 2, 4, 6%) of silver (Ag) was synthesized by simple co-precipitation method. The effect of Ag doping on structural, morphological and compositional properties of MnCO3 were investigated. XRD results revealed that the synthesized samples have hexagonal-rhombohedral structure and the peaks are shifted towards higher angles with increasing Ag content. The pure MnCO3 exhibited microsphere like morphology with the size in the rage of 0.8–2.5 μm. XPS analysis confirmed the presence of Mn, C, O and Ag elements. The specific capacitance values are calculated and 4% Ag-doped MnCO3 electrode exhibited a high specific capacitance of 554.6 Fg-1 at a current density of 0.5 Ag-1, good rate capability of 54.74% and excellent cycle stability of 87.22% capacitance retention after 1000 cycles. From these results, Ag-doped MnCO3 could be preferred as the potential competitor for future electrochemical supercapacitor devices.

Pure and cobalt (Co)-doped tin oxide (SnO2) nanoparticles were prepared by using a simple co-precipitation method, and the effect of doping on structural, morphological and optical properties was studied. X-ray diffraction revealed a cassiterite tetragonal SnO2 structure with the space group of P42/mnm and without crystalline phases for the samples-doped with higher concentrations. The average crystalline size was found to be between 26.4 nm and 23.1 nm. Fourier-transform infrared spectra depicted the presence of O–H, C–H and Sn–OH absorption bands. It was observed from ultraviolet–visible spectra that the optical band gap values were decreased from 3.69 eV for pure SnO2 to 3.47 eV for 7% Co-doped SnO2. The photolumenescene emission spectra showed that the defect- and emissions-related peaks and the intensity of the peaks decreased with increasing Co concentrations. The presence of tin, oxygen and Co species were found from energy dispersive x-ray spectra. The photocatalytic activities of pure and Co-doped SnO2 nanoparticles were investigated by studying the photodecomposition of brilliant green dye, an organic pollutant. The 7% Co-doped SnO2 had higher photocatalytic activity compared to the pure SnO2, and a maximum degradation efficiency of 91% has been obtained under visible light irradiation.

Highly transparent and conducting samarium doped cadmium oxide (CdO: Sm) thin films were deposited on glass substrates at room temperature by radio frequency (RF) magnetron sputtering technique using CdO(90 wt%): Sm2O3(10 wt%) mixed alloy target in pure argon atmosphere. The influences of RF power and Sm incorporation on structural, morphological, optical and electrical properties of the films were investigated. X-ray diffraction analysis revealed that the deposited films are polycrystalline nature and RF power has a large impact on the preferred orientation of the films. The X-ray photoelectron spectroscopy studies confirmed the presence of divalent cadmium (Cd2+) and trivalent samarium (Sm3+) in the deposited film. It is found from the atomic force microscopic analysis that the films were highly smooth with low roughness value of about1.3 nm. High transmittance value greater than 80% was retained by the films in visible and near infrared regions and the band gap value decreased with the increase of RF power by quantum confinement. At the moderate RF power of 200 W, the film has low resistivity of the order of 1.283 × 10−4 Ω cm, high mobility 157.8 cm2/V and a high figure of merit 769.04 (Ω cm2)−1 which could be used as an alternative TCO layer for future optoelectronic devices.

Cerium (Ce) doped SnO2/g-C3N4 composites were synthesized by a facile hydrothermal method. The obtained Ce doped SnO2/g-C3N4 composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–Vis), scanning electron microscope (SEM), energy dispersive spectra (EDS), elemental mapping and X-ray photoelectron spectroscopy (XPS). An electrode made of Ce doped SnO2/g-C3N4 exhibited a maximum specific capacitance of 274 F/g at 1 A/g current density. The supercapacitor device fabricated by using Ce-SnO2/g-C3N4//Activated Carbon as electrodes has showed an energy and power densities of 39.3 W h kg−1 and 7425 W kg−1. The asymmetric device gives the retention of 84.2% after completing 5000 cycles. When the same, Ce-SnO2/g-C3N4, composite is used as a photo-catalyst for reduction of methylene blue dye under visible light irradiation, exhibits a higher degradation efficiency of 98% which is higher efficiency compared to all other synthesized samples.

In this article, we synthesize the bifunctional materials of various transition metals (TM) (Co, Ni and Mn) doped SnO2@MoS2 composites for enhanced energy storage and improved photocatalytic activity for removing organic pollutants. Herein, we use a facile hydrothermal method for sample synthesis and the physico chemical properties of the synthesized samples were investigated in detail using various analytical tools. The energy dispersive X-ray spectra and elemental mapping confirmed the presence of species in the synthesized samples. X-ray photoelectron spectroscopy analysis revealed the corresponding energy state of various TM doped SnO2@MoS2 samples. The Mn doped SnO2@MoS2 composite exhibited a higher specific capacitance of 242 F/g at a current density 0.5 A/g. The capacitance retention of 83.95% was observed after 5000 continuous charge/discharge cycles. Further, the Mn doped SnO2@MoS2 composite had higher degradation efficiency (97%) compared to all other samples using methylene blue as an organic dye under visible light irradiation. Henceforth, this study demonstrates the optimum concentration of Mn doped SnO2@MoS2 composite is the outstanding bifunctional materials for supercapacitor and photocatalytic applications.

Synthesis of high energy density and long durability electrode materials are huge urgency for futuristic hybrid supercapacitors (HSCs). In the present work, self-assembled three-dimensional (3D)-mesoporous regimented pristine and neodymium (Nd) doped α-Mn2O3 microspheres (MSs) are prepared by simple hydrothermal method. Due to uniform morphology, presence of oxygen vacancies, mesoporous robust structure, and optimum doping (Nd5%-doped Mn2O3 3D-MSs) offers a high specific capacitance of 862.14 F g−1 (431.07 C g−1) at 0.5 A g−1 with superior cycling retention of 97.30% after 2000 cycles. Additionally, a pouch-type HSC device is fabricated using Nd5%-Mn2O3 3D-MSs as a battery-type positive electrode and activated carbon (AC) as a capacitive-type negative electrode. The fabricated device delivers a maximum energy density of 32.26 Wh kg−1 at a power density of 800 W kg−1 with superior cyclic retention and exhibit a little loss of 4.56% after 10,000 cycles. This superior performance is due to robust microstructures that can alleviate swelling and shrinking of active material at cycling test. Two pouch-type HSCs are connected in series to power light-emitting diodes (LEDs) for real-time applicability. Overall, this study demonstrates that rational doping, porous architecture, oxygen vacancies, and robust micro-nano structure greatly assist to achieve high energy density as well as long life HSCs devices.

A simple co-precipitation method has been used to synthesis SnO2 and different transition metal (Fe, Cu and Zn) doped SnO2 spherical nanostructures. The influence of doping concentration on the structural, optical, functional and morphological properties were carefully analysed by using X-ray diffraction, Fourier Transform Infrared Spectroscopy, UV–Visible spectroscopy and Scanning Electron Microscopy studies. The XRD pattern declared the formation of cassiterite rutile SnO2 with tetragonal structure. No impurity peaks correspond to the transition metal dopant was observed in the doped SnO2 samples. The average crystallite size was found to be 27.2, 24.1, 22.3 and 21.8 nm for pure and Fe, Cu and Zn-doped samples, respectively. The EDX spectra and element mapping assessed the presence of Sn, O, Fe, Cu and Zn species. The SEM images showed the spherical morphology for the synthesized pure and TM-doped samples. X-ray photoelectron spectra confirmed the electronic state and binding energy of the Sn, Cu, Zn, Fe and O. The electrochemical performance of the prepared electrodes were evaluated by galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy. The nanostructured Fe doped SnO2 electrode revealed a favorable specific capacitance of 270 F/g at a current density of 0.5 A/g and also it has excellent cycling stability of 98% retention over 2000 charging discharging cycles.

Transparent and conducting thin films of pure and gadolinium(Gd) doped cadmium oxide (CdO) were deposited on glass substrates by RF magnetron sputtering at ambient temperature to develop indium free, alternate transparent conducting electrode for optoelectronic devices. The impacts of Gd doping and film thickness on physical properties of the deposited films were investigated. Mechanism of transmittance, conduction and the scattering process were also discussed. The films showed cubic structure with predominant orientation along (111) plane. All the deposited films were smooth and homogeneous with decreasing roughness from 2.23 nm to 1.69 nm for Gd doped CdO thin film. Pristine CdO film showed peculiar morphology of nano pyramidal shaped grains on the surface. The average transmittance of the films increased from 79% to 88% with the doping of Gd. The Gd doped CdO (GCO) film at a thickness of 900 nm exhibits a maximum transmittance of 93% in visible range. The Gd doped CdO film deposited at a thickness of 900 nm showed the best optoelectronic properties with high average transmittance (88%) and low resistivity (7.203 × 10−5 Ω cm). This result indicates that the Gd doped CdO thin films deposited with suitable thickness can be used as an alternative for high performance TCO in various optoelectronic devices.

In this paper, the structural and magnetic behavior of Ni/Mn co-doped ZnO nanoparticles (NPs) synthesized by co-precipitation method are presented. Powder X-ray diffraction data confirm the formation of a single phase wurtzite type of ZnO structure for all the synthesized Ni, Mn doped and co-doped ZnO nanoparticles. The average crystallite size of NPs is found to be 26–38 nm. FTIR and UV spectroscopic results confirm the incorporation of the dopant into the ZnO lattice structure. Photoluminescence intensity varies with doping due to the increase of oxygen vacancies. Furthermore, M-H curve demonstrates that the Ni/Mn co-doped ZnO NPs possess obvious ferromagnetic characteristics at room temperature. Our study enhances the understanding of the novel performances of transition metal co-doped ZnO NPs and also provides possibilities to fabricate spintronic devices.

We report systematic studies of the magnetic properties of Ni and Mn co-doped ZnO nanoparticles prepared by co-precipitation method. Structural characterization reveals that Ni and Mn ions substituted into ZnO lattices without any secondary phases formation. Photoluminescence and Raman spectra shows that the Ni/Mn were doped into the ZnO lattice resulting slight shift in near-band-edge emission. Moreover, the novel Raman peak at 586 cm−1 indicates two kinds of cations via doping that could affect the local polarizability. Magnetic measurements of the nanoparticles exhibits ferromagnetic behavior at room-temperature.