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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.

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.

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.

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.

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 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.

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.

Herein, we present the facile synthesis of different content of chromium (Cr)-doped CdS quantum dots (Cr@CdS QDs) using microwave route within 15 min. The synthesized Cr@CdS QDs were investigated for structural, morphological, opto-dielectric, and electrical natures. X-ray diffraction confirms the monophasic hexagonal system of Cr@CdS and the sizes of crystallites are calculated to be 8.72, 7.04, 8.84, 6.56, 5.96, 6.52 and 6.99 nm for 0.0, 0.5, 1.0, 5.0, 10.0, 15.0, and 20.0 wt% Cr@CdS samples. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies reveal the quantum dots size spherical shape morphology of synthesized Cr@CdS samples and the size is noted in range of 8.5–8.1 nm. The lattice spacing and orientation of grown QDs was also evaluated by high-resolution TEM and Selected Area Electron Diffraction (SAED) pattern. Diffused reflectance spectra were recorded and Kubelka–Munk theory is employed to estimate the energy gap. The energy gap was estimated between 2.4 and 2.46 eV for Cr@CdS QDs. Photoluminescence (PL) emission spectra own an strong emission peak in both spectra recorded at two different excitation wavelengths and revealed that the PL emission intensity is quenched with Cr doping in CdS. Dielectric and ac electrical studies shows the dependence on frequency and Cr content doping, and constant values are enhanced from 14 to 17 at 4 MHz. The prepared Cr@CdS QDs will be highly useful as sensitizers in solar cell, spintronics, and optoelectronics.

PbS films in undoped state and with various Eu contents (1 wt.%, 3 wt.%, and 5 wt.%) have been coated effectively on insulating glass substrates by a nebulized spray pyrolysis route. The effects of Eu doping on various properties including the photosensitivity of the PbS films were systematically analyzed. X-ray diffraction (XRD) analysis of the materials revealed a polycrystalline nature with crystallites showing simple cubic structure oriented along (200) direction. Based on the XRD data, the crystallite size, dislocation density, and lattice strain of the films with different doping concentrations were calculated and are consistently discussed. The secondary phase Eu3O4 formed when the Eu doping level was higher in the host solution. The Raman peaks detected at 190 cm−1, 236 cm−1, and 465 cm−1 confirmed formation of PbS. Scanning electron microscopy was used to reveal the morphology of the films as a function of the dopant concentration. Important optical properties including the bandgap, absorption coefficient, dielectric constant, index of refraction, and coefficient of extinction of the films are systematically reported. Optical study of the films revealed a variation of the bandgap from 2.14 eV to 2.81 eV with increasing Eu doping level. The 3 wt.% europium-doped PbS film showed better photosensitivity at 100 W/m2 compared with the other films based on current–voltage (I–V) measurements.

Cd–ZnO–Na alloy nanostructured thin films were synthesized via sol–gel spin coating method on glass substrates and the effect of Na (1, 2 and 3 wt%) doping variation on linear, nonlinear optical, opto-dielectric, and emission properties of the films was investigated. The variations in physical properties with different Na doping concentrations were analyzed using X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscope (SEM), FT-Raman, UV–Vis, and photoluminescence spectroscopy. From XRD patterns, it was observed that the growth of the films occurs along (002) plane with hexagonal wurtzite structure. High percentage of transmittance (viz. 85 to 90%) was recorded for all as grown films. However, the estimated bandgap energy of the films was found to decrease from 3.37 to 3.30 eV with increasing Na doping concentration from 1 to 3 wt%. Emission spectra of the films show an intense and sharp peak near band emission (NBE) at 389 nm whereas a low intense peak was observed at 475 nm. The intensity of NBE peak specifies the significant enhancement in photoluminescence properties of the grown films with increasing Na doping concentrations. Nonlinear optical parameters of the Cd–ZnO–Na films such as χ3 and n2 showed substantial improvements, which were deduced and obtained in the range 1.11 × 10–14–1.91 × 10–12 esu and 5.20 × 10–13–3.19 × 10–11 esu, respectively. The achieved improvement in the grown ZnO films via co-doping with Cd and Na makes them highly suitable candidates for optoelectronics devices applications.

Spinel ZnMn2O4 nanoparticles (ZMONPs) were successfully synthesized using a microwave-assisted chemical route. X-ray diffraction (XRD) revealed the growth of ZMONPs along the (211) plane with a tetragonal structure. The crystallite size was ~ 14 nm, estimated using the XRD data. Vibrational analysis confirmed the tetragonal structure of ZMONPs. Scanning electron microscopy images showed nanometer-sized particles, which was in agreement with the XRD results. EDX investigation of the samples demonstrated the good stoichiometric ratio of Zn, Mn, and O (1:2:4). The surface area and pore radius were also investigated in detail through Brunauer–Emmett–Teller analysis and were found to be 10.385 m2/g and 16.24 A, respectively. The direct band gap for the ZMONPs was estimated using Tauc’s relation and was found to be 2.07 eV, which is larger than that of bulk ZMO (1.91 eV). Dielectric constant and loss values decreased with increasing frequency, while conductivity increased with increasing frequency. The dielectric constant was found to be in the range of 17–25 considering the entire testing range. The dielectric constant value was larger than expected, which could be the result of quantum confinement.

The present work investigates the influence of sodium doping on structural, morphological, photoluminescence, linear, nonlinear (NL), and optical limiting (OL) parameters of NaxCd1−xS thin films (where x= 0.0, 0.5, 1.0, 2.5, and 5.0 wt%) deposited on glass substrates using spray pyrolysis route. X-ray diffraction and Raman analyses confirmed the hexagonal polycrystalline nature of films. Crystallite sizes were decreased from 30 to 17 nm with doping. Scanning electron microscopy (SEM) micrographs also confirmed the nanocrystalline spherical growth. Energy dispersive X-ray spectroscopy (EDS) and SEM mapping studies revealed the presence and homogeneous distribution of individual elements. Transmission of films is found to lie between 45 and 60%. Although the low doping caused the reduction of the effective band gap, higher doping caused a blue shift in band gap, with an associated reduction in crystallite sizes. The refractive index values are found within 1–2 in visible and their maximum values (in range 2.65–3.16) are observed at 2500 nm. Photoluminescence (PL) spectra showed broad emission peak at ∼520 ± 10 nm. Dielectric and NL analyses were also carried out. OL results were promising for the systematic gradual decrease of intensity from 100 to 72%, with doping for power regulating applications.

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 novel work, we discuss the effect of neodymium doping concentration on PbS thin films coated on glass substrates by a simple nebulizer spray pyrolysis method. The XRD analysis indicated that all the prepared PbS and PbS:Nd films possess polycrystalline simple cubic crystal structure along (200) preferential orientation and the estimated crystallites size tapered from 21 to 18 nm with growing Nd concentration. It is detected that Raman spectra of all films shows four characteristic mode at 186 cm−1, 281 cm−1, 326 cm−1, and 472 cm−1 certify the formation of PbS thin films. The micrographs obtained from scanning electron microscope indicated uniform particle on the surface of the films. Energy dispersive spectroscopy and mapping analyses confirmed the elemental composition. From the linear optical study by UV–Visible spectrometer exposed the absorption level of all the PbS:Nd films was constantly maintained in the whole visible and IR spectrum which is better for optical device fabrication. The rising of Nd content showed enhancement in band-gap as 2.13 to 2.41 eV. I–V characteristics of all the prepared films were done under dark and illumination conditions. Photosensitivity of the PbS films is enhanced after Nd doping, which result in enhancement of photo current. The results suggest that the proposed strategy can be applied to prepare high-performance photosensitivity thin films.

The facile synthesis of pristine and Terbium@Zinc oxide (Tb@ZnO) samples was produced by fast combustion route. The roughly spherical shaped morphology of Tb@ZnO was investigated by field emission scanning electron microscopy (FESEM) with agglomerated images of small size of particles. The dimension of particle shrinkages with increased the doping contents of Tb into ZnO lattice. The optical band gap of Tb@ZnO sample varies with the concentration of Tb and found to be decreased as 3.276, 3.267, 3.261 and 3.260 eV on increasing concentration of Tb from 1 to 5 wt%. The non-polar phonon mode with E2 symmetry was observed at 99 and 437 cm−1 while polar mode with A1 and E1 symmetry was reported at 330 and 580 cm−1, respectively, for pristine and Tb@ZnO samples. The photocatalytic activity of Tb@ZnO NPs has been investigated by the decolorization of methylene green (MG) dye under black light irradiation (367 nm). A remarkable photocatalytic performance of Tb@ZnO was noticed compared to the pure one and the highest percentage of activity was obtained for 1.0 wt% Tb@ZnO. Current outputs proposed the use of synthesized Tb@ZnO NPs in optoelectronic and photocatalyst applications.

Strontium-doped Cu2O thin films of different doping concentrations (0, 3, 5 and 7%) are deposited successfully with the help of Nebulizer spray technique. All the samples were characterized by XRD, AFM, Raman, UV–Vis, photoluminescence and Hall effect, and solar cell efficiency is calculated. From the XRD studies, the cubic structural phase of Cu2O is confirmed. The micrographs of AFM explain that the particles were uniformly distributed on the surface with homogeneous grains. The band gap value ranges from 2.17 to 1.95 eV as the doping concentration increases from 0 to 7%. The PL emission at ~ 630 nm also confirms the cuprous oxide phase. The deposited film exhibits p-type conductivity with low resistivity of 0.90 × 102 Ω cm and high carrier concentration of 22.7 × 1015 cm−3. A heterojunction solar cell of FTO/n-ZnO/p-Sr-doped Cu2O is fabricated, and the power conversion efficiency (η) is 0.75% for 7% Sr-doped film.

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.

In current article authors aim is to present an insight on structural, opto-nonlinear-limiting properties of Cadmium sulfide (CdS) thin films affected by various concentrations of tellurium (Te) doping. Hence, the thin films of pure and Te:CdS were fabricated by spray pyrolysis technique by keeping the substrate at 300 °C. X-ray diffraction and FT-Raman spectroscopy analyses confirmed the hexagonal phase of CdS. The values of Lave, ρave and eave are found in range of 18–20 nm, 2.6–3 nm−2 and 1.7–1.9, respectively. Furthermore, the energy dispersive X-ray spectroscopy/scanning electron microscopy mapping (SEM) confirmed the presence and homogeneous doping of Te in CdS. SEM study shows that the fabricated films are free from any pin holes and possess very fine nanostructures. The optical transparency of grown films was noticed ~ 70%, which is quite impressive for colored materials. The absorption index, refractive index values are found in range of 0.04 to 0.25, 1.25 to 3.2 in 200 to 2500 nm wavelength region. The direct energy gap of CdS was noticed to be reduced from 2.44 to 2.35 eV (ΔEg = 0.09) with Te doping content. Photoluminescence emission spectra contains an intense green emission band at ~ 528 ± 4 nm. The dielectric constant and optical conductivity were noticed in range of 1.5 to 10 and 0.02 to 0.6 (× 105), respectively. The values of third order susceptibility and nonlinear refractive index was found of the order of 10−10 esu. The output power of the 532 nm laser passed from films is found to be reducing with increasing the Te content in CdS films. Hence, the deposited films of Te:CdS will be more applicable as optical limiter in sensor device protection from intense lights.

The inner transition metal (ITM) neodymium (Nd)-doped tin sulfide (Nd:SnS) thin films with various Nd concentrations were coated by nebulizer spray pyrolysis (NSP) technique at 350 °C. All the coated films were analyzed for their structural, optical and photoelectrical properties. X-ray diffractometer (XRD) study showed (111) direction as the highly preferred orientation with orthorhombic crystal structure for all the films. The intensity of the peaks was found to increase until 5 at% Nd doping and then reduced for higher (7 at% Nd) doping concentration. Atomic force microscopic (AFM) images of the films proclaimed an increase in the surface and line roughness of the films by increasing Nd concentrations. Optical analysis on the films showed a variation in energy gap from 2.05 to 1.69 eV when the doping concentration increased from 0 at% to 7 at%. At 5 at% Nd doping, the photoluminescence (PL) spectra displayed a single strong emission peak at 723.1 nm with enhanced intensity corresponding to near-band-edge emission. All the SnS thin films exhibited p-type behavior with the lowest resistivity of ~ 4.311 Ω·cm and high carrier concentrations of ~ 1.441 × 1017 cm−3 for 5 at% Nd doping level as observed from Hall effect studies. Furthermore, fluorine-doped tin oxide (FTO)/n-CdS/p-Nd:SnS hetero-junction solar cells were prepared and the current–voltage curve in dark and light condition was obtained for the device. An efficiency of 0.135% was observed for the solar cell fabricated with 5 at% Nd-doped SnS thin film.

Herein, we present the fabrication and characterization of Gd:PbI2 thin films from low-cost material using a cost-effective spin-coating technique by taking the Gd content as 1.0, 2.0, and 3.0 wt% in PbI2. Single-phase and good crystallinity films oriented along the c-axis were confirmed by X-ray diffraction and FT-Raman spectroscopy. Size of crystallites increased with Gd concentration and was estimated to be in the range of 16–32 nm. Determination of morphology and size of grains (50–103 nm), and elemental confirmation were carried out by SEM/EDX analysis. Optical transparency of fabricated films was found to be in the range of 72–92%. The energy gap is reduced from 2.31 to 2.05 eV; this makes Gd:PbI2 films highly applicable in solar cells. The stable value of refractive index is estimated to be in the range of 1.85–2.3. Dielectric constant was observed to be reduced with doping and in the range of 2.5–35, and ac conductivity was also reduced by doping; however, both were enhanced with frequency. The values of χ(1), χ(3), and n(2) are found to be in the range of 0.15 to 2.5, 8 × 10−14 to 6.5 × 10−9, and 5 × 10−12 to 4 × 10−8, respectively.

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.

Lead iodide is one of the best room temperature radiation detector including applications in solar cell and photodetectors. Herein, we have fabricated the high-quality thin films of pure and Nd:PbI2 through a simple and cost-effective spin-coating route and investigated their key properties. X-ray diffraction study confirms the growth orientation of all films along c-axis/(001) plane and single phase of 2H-PbI2 Polytypes with the crystallites of size in range of 21–31 nm. Further confirmation of growth and phase was carried out through FT-Raman analysis. EDX and SEM mapping was also carried out to confirm the Nd doping and its homogeneity in the films. SEM provides a clear view on the surface morphology of grown films and grain size was found in the range of 54–71 nm. Optical measurement shows high transparency, i.e., ~ 90% for grown films in visible to NIR region. The direct bandgap is observed to be enhanced with Nd doping from 2.45 to 2.58 eV; however, there is another bandgap which shows reduction with doping from 2.30 to 2.24 eV. This shows the possibility of existence of sub-energy bandgap in PbI2. The stable value of refractive index is evaluated ~ 2. The value of eʹ is found to varies from 4 to 27 in the energy range of 1–2.5 eV. Optical limiting behavior of all films was also studied at two lasers of λ = 532 nm and 632.8 nm. Moreover, a device fabrication was done for electrical study and found the resistivity increases from 5.14 × 108 Ω-cm for pure to 1.18 × 109 Ω-cm for 5% Nd-doped PbI2.

Two-dimensional thermoelectric materials have been extensively explored in recent years for their potential to recycle waste heat into clean energy. Herein, we investigate the thermoelectric properties of hexagonal- and square-shaped monolayers of ZnO for renewable energy applications. These monolayers have been originated from the 110- and 011-facets of β-BeO type structured ZnO (β-BeO-ZnO). To execute this study, the electronic structures of these monolayers have been obtained within the framework of density functional theory (DFT). The results of electronic structures have been used to obtain the thermoelectric properties against chemical potential and temperature using the semi-classical Boltzmann transport theory (BTT). The high electrical conductivities and substantial Seebeck coefficient equivalent to 1500 μV/K have been recorded for 110-monolayer and 2716.75 μV/K for 011-monolayer. As a result, large thermoelectric power factors (PF) of magnitude 7.96 × 1010 W/mK2s at 0.49 eV for 110- monolayer and 4.63 × 1010 W/mK2s at 1.83 eV recorded for 011-monolayer. The PF of these monolayers has experienced a linear increase with the rise in temperature. Moreover, the thermoelectric figure-of-merit (zT) values have been recorded as ~ 1.02 and ~ 1 for 110- and 011-monolayer. The zT of 011-monolayer has been found to decrease for an increase in temperature beyond 450 K whereas zT of 110-monolayer has been found insensitive to change in temperature. This reveals the potential of ZnO monolayers (110-monolayer in particular) for applications in high-temperature thermoelectric devices.

Devising the two-dimensional (2D) structures of low-cost and non-toxic semiconductors for nanoscale technological applications has attracted substantial interest since the past decade. In this work, we design two types of ZnO monolayers derived from polar 0001-plane and nonpolar $$11\overline{2}0$$ -plane of the wurtzite structure, and explore their physical properties using the first-principles approach. Both ZnO $$\left( {11\overline{2}0} \right)$$ and ZnO(0001) monolayers exhibited cohesive and formation energies comparable to that of the stable wurtzite-structured ZnO. However, both monolayers exhibited substantially different electronic structures of band gaps 1.56 eV for single-layered ZnO $$\left( {11\overline{2}0} \right)$$ and 0.71 eV for ZnO(0001) monolayer. The edges of the valence and conduction bands of ZnO $$\left( {11\overline{2}0} \right)$$ monolayer are formed by parabolic bands, whereas almost flat band gap edges have been seen for ZnO(0001) surface. As a result, charge carriers associated with ZnO $$\left( {11\overline{2}0} \right)$$ monolayer exhibited relatively lighter effective mass than ZnO(0001) monolayer. The ZnO(0001) monolayer exhibited symmetrical bond lengths and subsequently isotropic optical spectra, whereas asymmetrical bond lengths and anisotropic subsequent optical spectra have been recorded for ZnO $$\left( {11\overline{2}0} \right)$$ monolayer. The optical absorption recorded for the designed monolayers has been found higher than their bulk counterpart. The refraction spectra indicated these monolayers of transparent behavior over a significant range of the electromagnetic spectrum. These fascinating features of ZnO $$\left( {11\overline{2}0} \right)$$ and ZnO(0001) monolayers suggest them suitable for applications in electronic and optoelectronic devices.

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.

In this present research work, we report the preparation of successfully synthesized ZnO films as pristine and doped with Al(Al-ZnO) on glass via facile, eco-friendly, and controllable SILAR method. A systematic evolution of structural, surface morphology, composition, photoluminescence and ammonia gas sensing behaviour of the system was investigated with a variation of Al dopant. XRD examination disclosed polycrystalline nature with the hexagonal system of all films and crystallite size was noticed between 37 and 51 nm. EDX study approves the presence of Al doping in ZnO. Surface morphological tests through SEM presented the formation of nanoparticles and nanorods with a variation of Al content. The photoluminescence study revealed that due to Al doping the PL intensity was quenched which signifies the reduction of defects in the films. It was shown that the estimated values of the energy gap are enlarged to 3.12 from 3.01 on rising the Al content till 3wt.% and finally decreased for 5wt.% Al content. The gas sensing analysis showed that Al doping content was made to drastically increase the gas sensing response. Compared with other dopant levels, the 3wt.% Al-ZnO nanorods unveiled the uppermost retort when tested to 100 ppm ammonia (NH3) gas concentration at room temperature.

Herein, we are reporting a facile chemical process to attain high-grade PbS spherical nanoparticles with diverse La doping contents at low temperature and named it as La@PbS SNPs. All the prepared La@PbS SNPs samples are of single-cubic phase with good crystalline nature confirmed from XRD and Rietveld refinement. Along with lattice constants several other structure-related parameters like size, dislocations, strain, stacking fault, density and specific surface area were calculated. EDX and SEM-e-mapping analyses confirm the presence of La in PbS with homogeneous distribution throughout the samples. For morphological investigation FESEM was employed, which approved the synthesis of SNPs of low dimensions at all La contents. FT-Raman analysis shows characteristics vibrational modes related to cubic-PbS and that is in good accordance with XRD outcomes. Energy gap values were determined through Kubelka–Munk procedure and noticed to lie between 1.01 to 1.103 eV ( $$ \Delta E = 0.093 \;{\text{eV}}) $$ , this shows a very minute shift in energy gap with La doping in PbS. Dielectric constant ( $$ \varepsilon ' $$ ), loss tangent, dielectric loss and impedance values were assessed and stable values of $$ \varepsilon ' $$ were noticed in 20–50 range and 5.0 wt % La@PbS SNPs possesses highest value. The ac electrical conductivity analysis revealed enhancement with La content in PbS. The correlated barrier hoping mechanism was involved in the prepared La@PbS SNPs. Furthermore, the DC electrical properties were studied and discussed the impact of La content.

This work reports the changes in the properties of Ag-doped SnS thin films (SnS:Ag), and CdS/SnS solar cells with an Ag dopant concentration in the absorber varied from 0 to 6 wt.% in steps of 3 wt.% prepared by the nebulizer-assisted spray pyrolysis method (NSP). X-ray diffraction (XRD) studies confirm the SnS:Ag (3 wt.%) thin film has a higher crystallite size than the undoped and SnS:Ag (6 wt.%) thin film. An atomic force microscope (AFM) image shows SnS:Ag (3 wt.%) film possesses larger-sized grains than other samples. The energy-dispersive X-ray analysis (EDS) confirms the presence of the constituent elements in the SnS:Ag thin films. PL analysis revealed the films possess the band edge as well as the other defect-related emissions of SnS. The Ag doping facilitates the tunability in absorption and decreases in optical bandgap for the SnS:Ag (3 wt.%) film. Hall measurements provide the low resistivity of 3.31 Ωcm, the high charge carrier concentration of 1.56 × 1017 cm−3, and high mobility of 12.1 cm2 V−1 s−1 for 3 wt.% Ag-doped SnS film. The better photovoltaic conversion efficiency of 0.285% was observed for the device prepared with SnS:Ag (3 wt.%) thin film compared to other samples due to enhanced absorption, optimum bandgap, and better electrical properties.

Cadmium sulphide is known to have tremendous applications towards optoelectronic and nonlinear devices. Hence, here we have facilely casted the CdS films with diverse Se contents through low-cost spray pyrolysis technique. XRD study defends mono-phase formation of CdS having hexagonal system at all Se doping contents. Scherrer equation was employed to evaluate crystallite size in range of 15–25 nm. Vibrational study reveals the presence of fundamental modes of vibration of hexagonal CdS. EDX and SEM mapping studies approve the existence of Se and its homogeneous distribution all over the film. SEM micrographs shows the nanoscale grains formation on film surface and the size is increasing with Se doping. Optical study revealed that the grown films are of optimal quality with transparency in range of 60–75% with low absorbance and reflectance values. The refractive index values are noted to varied from 1 to 2.7 with wavelength and noticed to be reduced on Se content in UV–Vis region. The reduction in direct and indirect energy gap was found from 2.46 to 2.34 eV and 2.21 to 1.96 eV, correspondingly due to Se. PL emission profile contains an emission band at 528, 529, 529, 530 and 546 nm for 0.0, 0.5, 1.0, 2.5, 5.0 wt% Se:CdS films. Dielectric constant and loss were estimated. The nonlinear refraction (n2) and absorption coefficient (β) and third-order nonlinear susceptibility $$(\chi^{3} )$$ values were determined using Z-scan and observed in order of 10–8 cm2/W, 10–4 cm/W and 10–3 esu, correspondingly. The high values of $$\chi^{3}$$ propose the films for nonlinear applications.

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.

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.

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.

Herein, we report the detailed optoelectronic characteristics of low cost fabricated pristine and 1, 5, 10, and 15 wt% Mg-doped ZnO films on the FTO substrate (MZO/FTO) through the spin coating technique. High crystallinity and single phase of the film were confirmed by X-ray diffraction investigation. The average crystallite size was in the range of 46–78 nm. Homogeneous distribution of Mg doping in ZnO was approved by elemental mapping analysis. The fiber-like surface morphology was confirmed by the scanning electron microscopy analysis. Optical transparency was observed in the range of 40–80% for the fabricated films. The optical band gaps for direct and indirect transitions obtained from Tauc’s relation are in the range of 3.103–3.283 eV and 2.423–2.968 eV, respectively. It is also observed that the energy gap of MZO films decreases with an increase in Mg doping from 1 to 15%. The respective stable values of absorption and refractive indices are obtained in the range of ∼0.036–0.088 and ∼1.71–2.1. The linear and nonlinear optical susceptibilities as well as the nonlinear refractive index values were calculated. Additionally, Z-scan measurement was carried out at 532 nm wavelength. The nonlinear absorption coefficient and the imaginary part of third-order nonlinear susceptibility were estimated and corresponding values are obtained in the range of 0.35–123 (×10−5) cm/W and 0.084–29.7 (×10−8) e.s.u., respectively. Moreover, the optical limiting threshold values were obtained in the range of 2.57–6.34 kJ/cm2. The MZO/FTO films are showing strong optical limiting behavior compared to pristine. The output results suggest that MZO films are better contenders for optoelectronic applications.

In this work, very first attempt has been made to investigate the electronic, spectroscopic and nonlinear optical properties of l-threoninium picrate (LTHP) molecule by exploiting vital computational methods such as HF, B3LYP and range-separated functionals (CAM-B3LYP and LC-BLYP) with 6-31G* basis set. The calculated values of IR and Raman vibrational frequencies were found to be in a good agreement with experimental results. Time-dependent density functional theory has been applied to calculate the electronic and photophysical properties such as excitation energy, dipole moment and frontier molecular orbital (FMO) energies of LTHP. The excitation energy value calculated by CAM-B3LYP is at ~ 351 nm that in close harmony with experimental value (i.e., 356 nm). Total/partial DOS was determined using GGA/BLYP. The values of μtot, αtot, Δα, β0 and βtot were estimated and discussed. The μtot and βtot are found to be 3 and 51 times higher than urea molecule, respectively. The FMOs, molecular electrostatic potential and global reactivity descriptors were also calculated and discussed. All these results suggest that the LTHP would be a good candidate for optoelectronic applications.

Phenol red dyed bis thiourea cadmium acetate (BTCA) crystals of ∼30 × 10 × 6 mm dimension have been grown for the first time using the slow evaporation solution technique. Diffuse reflectance measurements show absorption bands at 363 and 563 nm in the doped crystal. Optical energy gap was calculated to be 4–5 eV. Photoluminescence spectra were recorded using 320 nm excitation source. The chemical etching study was done and etch pit density was found to be reduced from 4.5 × 103/cm2 (pure) to 3.0 × 102/cm2 (dyed). Mechanical strength is increased from 74.1 kg/mm2 for pure to 94.7 kg/mm2 for dyed crystals. The enriched properties of BTCA in the presence of dye suggest that the dyed crystals will be more applicable compared to pure crystals.

Herein, we report the microwave-synthesis of pure and lanthanum (La3+) doped PbI2 nanostructures. Single phase and good crystallinity confirmation was done using X-ray diffraction and FT-Raman spectroscopy analyses. Presence of La in the final product was proved by energy dispersive X-ray spectroscopy and homogeneous doping of La was seen in EDX elemental mapping. Vibrational modes of final products gets shifted compare to bulk values which evidently specify more relaxed nanostructure formation. The morphology was determined by scanning electron microscope analysis which was nanorods (NRs) of dimension in range of 70–100 nm of pure. However, when doped with 1% La the formation of nanosheets (NSs) are found to be more dense with well defined hexagonal morphology and the average thickness is found to be reduced which is ~ 57 nm and size is increased. Ultra violet–visible–near infrared measurement was done and the energy gap was computed, which are in range of ~ 2.93 to 3.26 eV. Photoluminescence emission spectra was recorded at $${\lambda _{exc}}=221\;{\text{nm}}$$ . PL emissions positioned at ~ 470 ± 2 and 525 ± 7 nm are corresponding to blue and green emissions in NSs. An enhancement in values of dielectric and electrical conductivity was observed due to doping.

The microstructure and mechanical properties of Sn-3.5Ag-0.5Cu (SAC355) solder alloy reinforced with different amounts of graphitic carbon nitride nanosheets (GCNNs) are assessed. The as-synthesized GCNNs were examined by a scanning electron microscope and X-ray diffraction techniques. A set of composite solders were fabricated by adding GCNNs with different concentrations (0 wt.%, 0.25 wt.%, 0.5 wt.%, and 1.0 wt.%) to SAC355 solder alloy. After a solution heat treatment, samples were immediately aged at temperatures ranging from 343 K to 403 K for 2 h followed by water quenching at 273 K. The mechanical properties of the composite solders were assessed using the indentation hardness test. The experimental results showed that the minimum creep rate values estimated from hardness data increased progressively with increasing weight percentage of GCNNs and/or aging temperature. The homogeneous distribution of GCNNs in the composite solders allows microscopic defects such as cracks to develop throughout the solders leading to higher creep rate values. The calculated values of the stress exponent and the activation energy for the creep process indicated that the creep rate controlling process depends on dislocation core diffusion in the tin matrix.