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Lead-free Cs3Bi2I9 material is chosen to eliminate its single-phase synthesis difficulty and implementing Cs3Bi2I9@SiO2 towards bioimaging applications. Cytotoxicity of Cs3Bi2I9@SiO2 was demonstrated using MTT assay in L929 fibroblast cells.

Herein, we present the development and characterization of Yttrium oxide (Y2O3) films and Al/Y2O3/n-Si heterojunction diodes at various substrate temperatures using a low-cost facile jet nebulizer spray pyrolysis (JNSP) technique. The X-ray powder diffraction (XRD) pattern proved polycrystalline films of Y2O3 with a cubic structure. Field emission scanning electron microscope (FESEM) images reveal very fine nanograins formation in Y2O3 films at all temperatures. Scanning probe microscopy (SPM) analysis shows very low roughness of all films. The detailed compositional/homogeneity analysis was done via energy dispersive X-ray (EDX)/e-mapping analysis. All the films exhibited a sharp absorption edge at ∼ 280 nm, and the estimated energy gap values were noticed between 4.5 to 5.5 eV. Moreover, the observed photoluminescence (PL) spectrum indicated that the intensity of emission peaks quenched ∼ 3 times, indicating the reduction of defects with substrate temperature. From the current – voltage (I-V) characteristic, the calculated ideality factor (n) value was noticed to be drastically reduced from 7.66 and 2.87 on increasing the substrate temperature. Further, the diode ideality factor, series resistance (Rs) and barrier height (ФB) were obtained from Cheung's method. The results revealed that the developed Al/Y2O3/n-Si heterojunction diode is a promising contender for optoelectronic devices.

In this article, the thermoelectric properties of five different polymorphs of gallium phosphide (GaP) such zinc-blende (zb-GaP), wurtzite (wz-GaP), sphalerite (sp-GaP), Beryllium oxide (β-BeO-GaP), and Silicon carbide (SiC-GaP) have been reported in detail. In this regard, the prerequisite electronic structure calculations have been performed in the framework of density functional theory (DFT), whereas the results for thermoelectric properties have been obtained via Boltzmann transport theory (BTT). We found that these GaP polymorphs exhibit relatively higher electrical conductivity corresponding to holes as a result larger power factors (PFs) have been realized for n-type doping than p-type. The highest values of PF corresponding to n-type doping have been recorded as 27.492 × 1010 W/mK2s, 27.999 × 1010 W/mK2s, 29.491 × 1010 W/mK2s, 15.706 × 1010 W/mK2s, and 26.557 × 1010 W/mK2s respectively, for zb-GaP, wz-GaP, sp-GaP, β-BeO- GaP, and SiC-GaP. Moreover, their PF has been further enhanced by the increase in temperature. In contrast, the Seebeck coefficients (thermopowers) have been found relatively larger for p-type doping than n-type. The relatively large thermopowers and lower thermal conductivity for p-type doping have resulted in the enhancement of Figure-of-merit (zT) by holes rather than electrons. The highest zT values have been recorded as 0.997, 1.004, 0.998, 1.001, and 1.010 in the case of zb-GaP, wz-GaP, sp-GaP, β-BeO-GaP, and SiC-GaP respectively. Our study indicates the adequate potential of these different polymorphs of GaP for thermoelectric applications.

In this report, we studied the optical and dielectric properties of lanthanum doped lead sulphide (La@PbS) nanoparticles prepared by microwave assisted synthesis method. Crystallite phase of the prepared samples was confirmed through X-ray diffraction analysis. The uniformity and homogeneity of La@PbS was recorded by SEM analysis. The particles size were found to increase with La content. The band gap values vary between 0.87 and 1.00 eV and influenced by the La concentration. Dielectric constants are highly dependent on both the applied frequency and La doping, whose values ranges between 23 and 41. The AC conductivity studies show that, they follow Jonscher’s power law relationship, and their DC electrical resistivity decreases with La concentration. The outcomes suggested that the optoelectronics properties of prepared PbS samples can be widely tuned with La doping.

The polytypism of solids has been established as one of the most effective approaches to alter their physical properties. In this first-principles-based study, we practiced the polytypism of galliu...

Silica nanospheres have been explored much for drug delivery, photocatalysis, sensors and energy storage applications. It also acts as a template for Surface-Enhanced Raman Spectroscopy (SERS) substrates. Uniform nanostructures at low cost with high reproducibility are the major challenges in SERS substrate fabrication. In the present work, silica nanospheres were synthesized using stober method and deposited on to glass slides using Vertical deposition techniques. Different size/thickness of Silver (Ag) nanoparticles were deposited onto silica thin films using sputter deposition technique. The monodispersity of silica nanospheres and size of silver nanoparticles (10 nm, 20 nm and 30 nm) were confirmed by FESEM analysis. The structural properties were confirmed through XRD. UV–Vis analysis revealed that the plasmonic properties of Ag@SiO2 give high surface plasmons for 30 nm thickness of silver. The binding energy of Ag@SiO2 confirmed through XPS spectrum. The fabricated SERS substrates were used to detect Rhodamine 6G (R6G), Methylene blue (MB), Methylene violet (MV) and Methyl orange dyes as an analyte molecule with a limit of detection at about 10−11 mol/L. The addition of SiO2 nanospheres decreases the Ag oxidation rate and increases their stability. The maximum enhancement factor (1.5 × 107) achieved for 30nm thickness of Ag@SiO2. The results and technique establish the potential applications and reproducible SERS substrate.

Cobalt-doped ZnO (ZnO:Co) thin films were synthesized using the chemical bath deposition technique for their potential application in ultraviolet (UV) photosensing. All the prepared samples were characterized using XRD, FESEM, EDX, PL, XPS, and UV–Vis absorption techniques. The UV photosensing property of the thin films was examined under the illumination of UV light (365 nm). The structural and morphological investigations reveal that the ZnO:Co samples have a hexagonal wurtzite crystal structure with nanowire morphology. An increase in crystallite size and a decrease in the bandgap of the samples were observed owing to the replacement of the Co2+ ions in the regular sites of Zn2+. The PL spectra show some defect emission peaks in the visible region because of the occurrence of oxygen vacancies, which suggests a high photoabsorption property of the samples. The XPS study was performed to understand the existence of elements and their binding states in the fabricated thin films. The UV photosensing studies reveal that the highest responsivity of 0.918 AW−1 was achieved for the ZnO:Co (1%) sample.

The current work reports the synthesis of the Earth-abundant Copper Zinc Tin Sulfide (CZTS) absorber thin films at low temperature through modified spray pyrolysis technique without high-temperature annealing. The impact of carrier gas pressure during the synthesis of this potential solar absorbing material in the form of thin film is studied within the range of 0.10 to 0.20 Pa at a substrate temperature of 350˚C to understand the variation in its inherent characteristics. The deposited films were analyzed subsequently using X-ray diffraction, Raman spectroscopy, Scanning electron microscopy, Energy dispersive X-ray spectroscopy, Atomic force microscopy, and a UV–Vis spectrophotometer. The influence of the carrier gas pressure on the electrical property of the deposited films is also studied by analyzing its I–V characteristics. Structural and morphological analysis exhibits the formation of highly crystalline CZTS absorber film with good adherence on SLG substrate. The Raman analysis establishes the kesterite structure and the phase purity in the grown CZTS films except 0.15 Pa sample which shows the presence of a trace of Cu2S binary phase. The grain size as well as roughness of the deposited films is observed to increase with the gas pressure up to 0.15 Pa and decreased thereafter. The band gap of the film is found to decrease from 1.42 to 1.30 eV under the testing limits. The I–V characteristics of the deposited film at 0.15 Pa show higher current value than the rest of the samples. Apart from the study of influence of carrier gas pressure, this study also confirms the usage of the modified nebulizer-assisted spray pyrolysis technique as one of the economical fabrication methods for mass production of nontoxic CZTS absorber thin films that can be used in the development of environment-friendly low-cost solar cells.

The Er:NiO nanostructured thin films were fabricated using the spray pyrolysis method with 0.0, 2.5 and 5.0 wt.% dopant contents. Structural phase analysis of films reveals cubic structures with preferential growth along (111) plane at angle 2θ ~ 37.41°. Optical investigation of as-prepared films reveals redshift in optical bandgap (Eg) with an increase in Er contents due to the reduction of transparency in the visible region. The obtained Eg values are reduced from 3.95 to 3.80 eV with Er contents. The calculated values of χ 3 and n 2 were found between 1.81 × 10−15 to 4.56 × 10−11 esu and 5.13 × 10−14 to 5.45 × 10−10 esu, respectively. The prepared films are more suitable for optoelectronic applications due to the high transparency and Eg.

This paper presents experimental and density functional theory (DFT) investigations of Zn doping role in the Zn@CdO ternary system. Zn doped CdO nanostructures thin films with different Zn concentrations were successfully casted on glass substrates by sol–gel spin coating method. Cubic Zn@CdO structured ternary alloyed nanostructures thin films with 0.0, 1.0, 2.0 and 3.0 wt.% Zn concentrations were obtained. An enhancement in the lateral growth of CdO cauliflower-like nanostructures was observed after Zn addition which leads to a growth of nanostructured films with improved continuity. The effect of Zn doping on the linear optical parameters such as the optical band gap, the absorption index and the refractive index were also investigated. A remarkable blue shift in the band edge was observed as Zn is incorporated into the CdO matrix. In addition, the third order nonlinear optical parameters χ(3) and n2 were calculated and found to be about 2.89 × 10–12–4.33 × 10–14 esu and 2.89 × 10–12–4.33 × 10–14 esu; respectively. A DFT based Wien2k package was utilized to theoretically investigate the lattice parameters, the electronic structure, the absorption index and the refractive index of the Zn@CdO ternary nanoalloys. The role of Zn doping on the aforesaid properties was theoretically investigated for 3.125%, 6.25%, 12.5% and 25% Zn doping concentrations and was compared with the experimentally determined parameters. The combined theoretical and experimental investigations presented herein along with the detailed discussion of the obtained findings would provide a deep understanding of the opto-electronic behavior of the Zn doped CdO nanostructured films as well as their suitability for devices applications.

A successful flash combustion synthesis of NiO spherical nanoparticles with various contents of lanthanum (La) doping (La@NiO SNPs) with remarkably enhanced dielectric and electrical properties are reported. Single phase has been confirmed through X-ray diffraction and FT-Raman spectroscopic analysis. Increasing La content in NiO reduced the crystallite size by 341% to 6.65 nm from 22.70 nm. The composition of elements in the final product was assessed via EDX analysis. Moreover, monophasic La@NiO SNPs synthesis with size reduction was observed using field emission scanning electron microscopy (FESEM). A red shift in optical energy gaps (3.52–3.26 eV) was observed with increasing La contents from pure to 10 wt%. Capacitance (109–964 PF), impedance (9.41 × 104–1.67 × 104 kΩ), dielectric constant (100–967), dielectric loss (335–10666), and electrical conductivity (4–5 S/m) values were remarkably improved with La doping. The current (I)–voltage (V) characteristics of pure and La@NiO NPs were performed under the biased voltage of ±20 V. Current was noticed in the range of (3.81 × 10−4–9.91 × 10−3 amp) at pure, 1.0, 3.0, 5.0, and 10 wt% of La@NiO NPs. Enhancements in the dielectric and electrical properties of as-synthesized NPs make them suitable for optoelectronics uses.

This work reports the fabrication of Er@CdS films with 0, 1, 3, 5 wt% Er contents incorporated in CdS via spray pyrolysis route. The films were developed successfully with hexagonal structure and preferred growth orientation along (002) plane and crystallites sizes were found in the range 8–13 nm. Raman spectra showed the 1LO and 2LO vibrational bands centered at 300 cm−1 and 600 cm−1; respectively which confirms the synthesis of pure CdS. The optical band gaps of the films were found in range of 2.38–2.41 eV. A clear reduction in the band gap values is observed as with the incorporation of Er in the CdS matrix. In addition, Er@CdS thin films were utilized to construct a high performance photodetector (PD). The fabricated device shows enhanced visible light photodetection in comparison with the pure CdS films based device. The rise and decay time were detected in the range of 0.079–0.32 s and 0.099–0.32 s, respectively. Noticeable enhancements in responsivity (R) and the external quantum efficiency (EQE) were recorded, reaching maximum values as high as 4.95 A/W and 1150% for 3 wt% Er-doped films. This improvement in the PD performance may be due to the reduction in the defects and sulfur vacancies as a result of Er incorporation in the CdS matrix.

The authors report on the synthesis of Fe–NiO nanoparticles (Fe–NiO NPs) with a spherical shape via facile flash combustion synthesis. A structural test shows cubic formations of Fe–NiO NPs in all Fe concentrations. A reduction in crystallite size was observed with increasing Fe content from 27 nm to 12 nm. A vibrational study also indicates a cubic Fe–NiO NPs structure. However, slight shifts in peak positions were observed during Fe doping in NiO. The existence of Fe in NiO product was confirmed using energy dispersive X-ray (EDX) analysis, and its homogeneity in the final products was observed in scanning electron microscopy (SEM) e-mapping images. An X‐ray photoelectron spectroscopy (XPS) study was also carried out to confirm the incorporation of Fe in NiO matrix. A field-emission scanning electron microscopy (FESEM) study showed the formation of spherical nanoparticles in all Fe–NiO NPs samples. However, it was noted that the grain size reduced with increasing Fe content, which is in agreement with the X-ray diffraction (XRD) results. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) with a selected area electron diffraction (SAED) curve indicate very low-dimension NP formation from NiO. An optical test was performed based on the Kubelka-Munk theory along with an estimation of energy gas, which showed an increase of 3.5–3.75 eV with Fe content doping in NiO. Furthermore, the possibility of applying spherical Fe–NiO NPs as an electrode material was also assessed in a three-electrode assembly cell, and the results show that the NiO doped with 5% of Fe exhibited superior capacitance performance (F4, 297.67 F g-1) compared to the other samples.

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.

The development of materials in two-dimensions has been established as an effective approach to improve their thermoelectric performance for renewable energy production. In this article, we generated monolayers of the orthorhombic structured lead-chalcogenides PbX (X = S, Se, and Te) for room-temperature thermoelectric applications. The Density functional theory and semiclassical Boltzmann transport theory-based computational approaches have been adopted to carry out this study. The band structures of PbX monolayers exhibited narrow indirect bandgaps with a large density of states corresponding to their bandgap edges. Accordingly, substantial electrical conductivities and Seebeck coefficients have been obtained at moderate level doping that has caused significant thermoelectric power factors (PFs) and figures-of-merit (zT) ~1. The single-layered PbX showed anisotropic dispersion of electronic states in the band structure. A relatively lighter effective mass of charge carriers has been extrapolated from the bands oriented in the y-direction than that of the x-direction. As a result, the electrical conductivities and PFs have been observed larger in the y-direction. The optimum PFs recorded for single-layered PbS, PbSe, and PbTe in y-direction amounts to 9.90 × 1010 W/mK2s at 1.0 eV, 10.40 × 1010 W/mK2s at 0.82 eV, and 10.80 × 1010 W/mK2s 0.66 eV respectively. Moreover, a slight increase in p-type doping is found to improve the x-component of the PF, whereas n-type doping has led to improvement in the y-component of PF. Our results show an improved thermoelectric response of PbX monolayer (PbTe in particular) than their bulk counterparts reported in the literature, which indicates the promise of PbX monolayers for nanoscale thermoelectric applications at room temperature.

The effect of Nd doping (1, 3 and 5 wt%) on the structural, morphological, electrical and optical properties of NiO thin films deposited on glass substrates using nebulizer spray pyrolysis method are investigated. The X-ray diffraction study reveals cubic structure with an improvement in crystallinity upon the incorporation of Nd into NiO lattice. The films are > 50% transparent in the high wavelength region. The absorption spectra witnesses a sharp fall in the wavelength range, 300 nm

The structural and phase analysis of Li@ZnO nanostructures (NSs) were tested by X-ray diffraction (XRD) and transmission electron microscopy (TEM). TEM exhibits the mixture of nanoflakes and nanoparticles at 1 wt% Li, and spherical shaped nanoparticles at 7 wt%, respectively. TEM images show the nanoflakes with thickness (12–37 nm) and diameter of nanoparticles (38–63 nm) at 1 wt%, and size of nanoparticles with 34–84 nm at 7 wt%, respectively. Raman spectra exhibit the two major modes at 107 and 446 cm−1 were credited to longitudinal phonon modes. The optical bandgaps of 3.277–3.289 eV were evaluated from the optical spectra on basis of Kubelka–Munk function F(R) using Tauc’s relation. Red shift in absorption coefficient with wavelength indicates the optical bandgap decreased with increasing Li contents above 3 wt%. The photocatalytic activity of pristine and Li@ZnO NSs were investigated in the photodegradation of organic dye methylene green (MG) solution under UV irradiation. The photocatalytic study showed significant activity improvement in the Li-doped ZnO. The sample with 7 wt% Li-doped ZnO exhibited 6.1 times higher activity compared to neat ZnO sample.

The dielectric properties of pure and yttrium-doped PbS nanoparticles synthesized by the coprecipitation chemical synthesis route have been studied by several characterizations. X-ray diffraction patterns of samples were employed to estimate the crystallite sizes and intrinsic microstrains using Williamson–Hall (W–H) plot analysis. The crystallite size and intrinsic macrostrain values were evaluated in the range of 13.7–15.9 nm and 1.09 × 10–3–1.72 × 10–3, respectively, using W–H plots. The formation of nanoparticles, nanoflakes, sponge, and nanosheets were seen via scanning electron microscope (SEM). Energy dispersive spectroscopy (EDS) of 5.0 wt% confirms the Y: PbS sample elements' chemical composition and stoichiometry. The optical band gaps increase in the range of (0.93–1.17 eV) with an increase in the dislocation density. The higher values of dielectric constant (23.6–28.0), dielectric loss (37.6–176.8), loss tangent (2.7–8.6), and electrical conductivity [ 10.2 to ( 11.7) S/m] have been reported at the lower frequency. The highest electrical conductivity values were obtained in the range of [ 4.71 to ( 4.81) S/m] for as-prepared samples. The greater capacitance and impedance values were found at 3 kHz and decrease with increasing the frequency up to 10 MHz. The current–voltage characteristic curves of undoped and Y: PbS NPs were performed under biased voltage. The space charge current density was noticed in the range of (8.7 × 10–4–4.2 × 10–4 amp/cm2) at 1.0, 2.5, and 5.0 wt% of Y: PbS samples. The enhancement in the optical band gap and dielectric and electric properties on yttrium doping in PbS compared to pristine PbS NPs makes them suitable for optoelectronic applications.

The atomically thin two-dimensional (2D) materials have received remarkable attention for their promising applications in cutting-edge technological applications. In this article, we devised square and hexagonal shaped monolayers from the 110-facet and 011-facet of β-BeO type structured ZnO by separating them from the adjacent layers by a distance of 20 A. The energetic stability, lattice parameters, electronic and optical properties of these monolayers have been examined comprehensively using the density functional theory. In pursuit of this study, the wurtzite structured ZnO (w-ZnO) is first transformed into the β-BeO structure by applying a negative pressure of −5.4 GPa. The obtained monolayers exhibited comparable cohesive and formation energy to that of w-ZnO. The electronic structure calculations performed with the Tran-Blaha modified Becke Johnson exchange potential, demonstrated the 110-monolayer as indirect bandgap and 011-monolayer as direct bandgap semiconductors having bandgaps 1.59 eV and 1.72 eV respectively. The 110-monolayer exhibited isotropic optical coefficients whereas considerable anisotropy has been recorded in the dispersion of optical spectra of 011-monolayer. Also, these monolayers exhibited thermally stable excitons of binding energies estimated as 3.32 eV for 110-monolayer and 1.53 eV along the x-axis and 1.19 eV along the y-axis for 011-monolayer. Investigations of the refractive indices indicated both monolayers as of transparent nature. Our study provides the pathways to serve as a useful reference for designing low-cost and nontoxic 2D polymorphs of ZnO for optoelectronic applications in miniaturized portable devices.

The different contents (0 wt.%, 1 wt.%, 3 wt.% and 5 wt.%) of Nd @CdS films were casted using spray pyrolysis deposition procedure. The preferential orientation of crystallites along (002) for all films was noted by XRD profiles. The mean crystalline size (Davg), strain (ɛavg) and dislocation density (δavg) have also been evaluated using XRD results and discussed. The spherical shape morphology of nanoscale particles of Nd@CdS films were analyzed by FE-SEM, exhibits the increased grain sizes with Nd doping concentration. The optical band gaps (2.4–2.36 eV) were found to be decreased with increasing Nd doping content upto (3 wt.%) and increased at 5 wt.% The PL profile displays a stout intensity peak observed at 532 nm and week emission band at 638 nm. The dielectric constant, loss and loss tangent of pristine and Nd@CdS thin films were investigated by dielectric measurements. The optimum values of non-linear refractive index 1.06 × 10−10, 4.41 × 10−11, 3.44 × 10−11 and 1.85 × 10−10 were observed for Nd content varies from pristine to 5 wt.% respectively. Furthermore, optimum non-linear susceptibility values 7.31 × 10−12, 1.079 × 10−12, 4.53 × 10−13 and 1.36 × 10−11 were observed for 0, 1, 3 and 5 wt.% of Nd contents respectively in CdS. Such type of characteristics of Nd doped CdS thin films can be useful for optical devices.

The narrow bandgap PbSe has attracted a remarkable interest from the researchers in recent years for their potential optoelectronics and photovoltaic applications. In this article, we report the optoelectronic properties of cubic (NaCl-type) and orthorhombic (Cmcm- and Pnma-type) polymorphs of PbSe using the density functional theory based first-principles approaches. In accordance with the available literature, the NaCl–PbSe has been found stable in the ground state, whereas the Cmcm-, Pnma-types of PbSe have been realized at intermediate pressure of ~4.5 GPa. The electronic structures and optical spectra of these polymorphs have been determined using the Tran-Blaha modified Becke-Johnson exchange potential with and without spin-orbit coupling (SOC) effects. The inclusion of SOC has shown important effects on the electronic structures and consequently on the optical spectra. Despite SOC driven energy gap narrowing of these polymorphs, the direct bandgap nature of Cmcm-PbSe calculated with TB-mBJ has changed to indirect nature with the inclusion of SOC. Moreover, our results of the optical spectra of NaCl–PbSe have shown that this phase is isotropic, whereas a sufficiently high degree of anisotropy in the optical spectra has been recorded for Cmcm-, Pnma-types of PbSe. These PbSe polymorphs exhibited a high optical absorption that approaches as large as 106 cm−1. Moreover, our study provides comprehensive details of exciton binding energies and plasmon energies. This work is believed to provide a strong foundation to exploit the optoelectronic character of the studied phases of PbSe for next-generation optoelectronic and photovoltaic applications.

Herein, we have developed the thin Gd@PbI2 films on FTO via a facile spin coating route and subjected to various studies. The formation of (001) oriented hexagonal phase Gd:PbI2/FTO films was confirmed by X-ray diffraction & FT-Raman spectroscopy analyses. The size was determined through Scherrer formula in 11–16 nm range. The doping of Gd and its homogeneity was tested and approved by EDX and SEM e-mapping studies. The Gd doping impact on surface morphology was inspected via SEM images and found very low dimension grains formation throughout the films area. Tauc’s formula was employed to obtain energy gap and found in 2.46–2.74 eV for all Gd@PbI2 films. Absorption and refractive indices were estimated in 0.034–1.2 and 1.4–11 between 395 and 2400 nm wavelength regions. Respective dielectric constant and loss values were noted between 3.5 and 112, and 0.13 and 1.4, signify high dielectric constant and low loss values. The optical conductivity was calculated of 1016 order for all Gd@PbI2 films. SELF and VELF related values were also determined. The values of nonlinear optics related parameters were also calculated and revealed that the grown films are potential candidates for opto-nonlinear devices.

Cadmium Sulfide (CdS) is an excellent semiconductor for photonic devices and its optical and electrical properties are greatly affected by single element doping. In the current manuscript, the effect of potassium ion (K+) doping on linear and nonlinear optical traits of spray pyrolysis deposited CdS films was investigated. The X-ray diffraction (XRD) spectra reveal the increase of defects, decrease of crystallinity and crystallite size also change in growth orientation with K+ doping in CdS films. Moreover, the position of FT-Raman peaks was slightly blue shifted and morphology of films shows clusters of agglomerated CdS nanoparticles along with small size nanoparticles in the background as revealed from SEM images. The bandgap of K+-doped CdS films slightly broaden and shows improved transparency as compare to pure CdS films. The dielectric constants were found to be first decease for 2.5% wt. K+ doping and thereafter slightly increase for 5.0% wt. CdS films whereas optical conductivity decrease for all K+ doping concentrations. The photoluminescence intensity of CdS decreases and slightly blue shifted upon K+ doping, also a new emission band appears at 630 nm, indicating formation of new trap states in the bandgap of semiconductor. The 3rd order nonlinear properties elucidated through Z-scan technique reveals the increase of n2 and χ3 whilst decrease of β with increase of K+ content in CdS thin films.

Nanoscale materials are of a foremost desirability in functionalized materials research in almost all areas of science. Nanoscale materials with good biocompatibility and chemical stability possess biomedical usages which comprises drug carrier, cell/DNA parting, wastewater cleaning etc. Hence, magnesium-doped ZnO (Mg@ZnO) nanoparticles (NPs) were prepared by combustion route. Crystallization of Mg@ZnO NPs was investigated using X-ray diffraction and transmission electron microscopy. The particle sizes were in the range of 50–130 nm and 17.5–52.5 nm for x = 1 wt% and 4 wt% in MgxZn1-xO samples, respectively. The Zn2+ substitution by Mg2+ in ZnO increased oxygen vacancies and reduced free electrons concentration. The concentrations of dopant dependent optical band gaps were calculated using diffuse reflectance and found in the range of 3.258–3.278 eV. Antibacterial study of Mg@ZnO NPs was conducted against the Gram- + ve and Gram – ve bacteria and results revealed enrichment in antibacterial activity of Mg@ZnO NPs against all types of bacteria. In vivo test revealed that all Mg@ZnO NPs have no cytotoxic effects on liver and kidneys. Furthermore, photocatalytic activity was performed towards hazardous methylene green dye degradation under UV light irradiation. The presence of Mg in ZnO lattice remarkably improved its photocatalytic performance and the photocatalytic activity of Mg@ZnO ranged from 1.8 to 5.4 times higher than the activity of neat ZnO under the same reaction conditions. Facile synthesis of Mg@ZnO NPs was achieved successfully through flash combustion process and the prepared NPs were exploited for optical, biological and environmental applications. Enhancement of antibacterial, cytotoxicity and photocatalysis activity was observed in ZnO with Mg content doping. The outcomes present the Mg@ZnO NPs as an efficient material for opto-bio-environmental applications.

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.

Lead sulfide (PbS) is having tremendous applications in the field of optoelectronics. Hence, a facile low temperature synthesis of PbS with different contents of terbium (Tb) has been achieved and investigated for structure–optic–dielectric–electrical properties. The structure confirmation was observed through the X-ray diffraction and Rietveld refinement process which approved a monophasic cubic structure. Rietveld refinement gives a best-fitting profile of the prepared products. The crystallite size was estimated to be in range of 15–21 nm. FT-Raman study also approved the single-phase PbS with all characteristic modes. For further confirmation of composition, homogeneity, and Tb in the final product, the EDX/SEM e-mapping was carried out. The morphological investigation was carried out through SEM which revealed that the shape and size are greatly influenced by Tb content addition in PbS. The energy gap (Eg) was estimated in the range of 1.42–1.62 eV for all Tb@PbS, and the largest Eg value was observed for 0.5 wt% Tb@PbS. The dielectric constant values are calculated in the range of 16–25 in the tested frequency region. The ac electrical conductivity was enhanced with frequency, and a charge transport mechanism is related to a correlated barrier hoping model in the prepared samples.