Search

Nickel oxide (NiO) is found to have several fascinating applications in optoelectronics and spintronic devices. Hence, herein we facilely fabricated the NiO thin films with 0.0, 1.0, 2.5 and 5.0 wt.% Sr doping by low-cost spin coater at RT. The single-phase confirmation of Sr@NiO films was done by X-ray diffraction and FT-Raman analyses. The crystallite size was estimated through Scherrer rule and noted to lie between 13 to 31 nm. The broad Raman peaks indicate low dimension nanostructured films formation. Sr doping in NiO was detected by EDX spectra and its homogeneity in final film by SEM e-mapping. AFM analysis revealed nano-spherical grains in all films. The grown films were tested for optical transparency and noticed that the films are transparent viz. ~ 45 to 65% over 500 to 1400 nm wavelength region. The direct energy gap and refractive index was determined and lies between 3.74 to 3.84 eV and 1.6 and 2.2 in the visible, correspondingly. The values of dielectric constant were calculated in range from 2 to 60. The linear, third order nonlinear and nonlinear refractive index values are noted to be enhanced by Sr content in energy range from 1 to 4 eV. The enhanced energy gap and nonlinear activities signify the importance of the grown Sr@NiO films for optoelectronics.

Nickel oxide has tremendous applications in the field of biomedicine. In this study, NiO nanoparticles were synthesized with different Bi contents (NiO@Bi; 0.0–7.5 wt%), and multifunctional usages were investigated. Structural confirmation was conducted through XRD and Raman studies, which revealed a monophasic cubic system. With increasing Bi content, broadening of the XRD and Raman peaks were observed, indicating a reduction in particle size. The crystallite size was found to be in the range of 10–26 nm. The decrease in particle size was confirmed through dynamic light scattering measurement. The homogeneous distribution of all elements and the presence of Bi were detected by an EDX/SEM e-mapping study. Field emission electron microscopy confirmed the formation of spherical shape nanoparticles. The grain size was reduced from 30 nm to 10 nm with Bi content, in accordance with XRD and Raman results. The Kubelka-Munk method was employed to determine the effect of Bi content on the optical band gap of NiO. The energy gap was reduced with Bi content in the range of 3.32–3.50 eV. Antimicrobial and in vitro cytotoxic characteristics of the prepared NPs were also studied. The results revealed that all NiO@Bi NPs had negligible antimicrobial activity and no cytotoxic effects on both normal and activated splenic cells. The in vivo acute cytotoxicity study indicated no cytotoxic effects on liver and kidney functions. The prepared NiO@Bi NPs were implanted in living organisms without hepatic/renal toxicity, demonstrating excellent biocompatibility, cell viability, and superior quality of nanocrystals, suggesting that the prepared NPs are ideal candidates for antibacterial and biomedical applications.

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.

We reported a systematic study of the effects of Y doping BaTiO3 at Ba and Ti sites. We assessed the structural, electronic, and optical properties by employing first-principles calculations within the Tran–Blaha-modified Becke–Johnson (TB–mBJ) potential and generalized gradient approximation + U approaches. We calculated the lattice constants and bond lengths for pure and Y-doped BaTiO3. We explored the consequences of electronic structure and optical property modification because of Y doping in BaTiO3. Indeed, Y doping has led to various modifications in the electronic structures of BaTiO3 by inducing a shift of the conduction band through lower energies for the Ba site and higher energies for the Ti site. It was found that Y doping, either at Ba or at Ti sites, strongly enhanced the BaTiO3 dielectric constant properties. The transformation in bonding was explored via the charge density contours and Born effective charges. We used the state of art of polarization theory based on finite difference and Berry-phase approaches to investigate piezoelectricity. Y doping has increased the dielectric constants but canceled the piezoelectricity as they changed to metallic nature. We could look into the future for potential doping, preserving the semiconductor nature of BaTiO3 and increasing the permittivity with large dielectric loss.

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.

Herein, we report a novel method for the synthesis of pure and Tb-doped NiO nanocomposites with homogeneity using a non-toxic material, citric acid, via one-step flash combustion at 550 °C. The single cubic phase was determined by X-ray diffraction (XRD) analysis, confirming the high purity of the synthesized products. A systematic reduction and broadening of the XRD peaks was seen with increasing incorporation of Tb, indicating a decreasing particle size from 26 to 7 nm. The zeta potential was approximately −6.7 mV for pure NiO and 19 mV for 20% Tb-doped NiO NPs. The higher value of zeta potential indicates that the doped samples are more stable in aqueous media than undoped samples. FT-Raman spectra revealed the absence of impurity peaks and peak broadening with increasing Tb concentrations. All Raman modes were red shifted in comparison to bulk NiO. EDX/SEM mapping revealed the presence of Tb and its homogeneous distribution within NiO. FE-SEM and TEM confirmed the spherical morphology of NiO when doped with Tb. The surface area and pore volume of 5 wt% Tb-doped NiO NPs was determined to be 18.5 m2/g and 8.34 × 10−2 cm3/g, respectively. The energy gap varied with Tb-doping and noticed in the range of 3.5–3.6 eV. An intense single emission peak at 396 ± 5 nm for all Tb-doped NiO NPs was observed. Tb-doped NiO NPs demonstrated e r ′ values in range of 30–77 at 4 kHz and 20 to 41 at 6 MHz. Dark and photo current-voltage investigations revealed that Tb-doping significantly enhanced the electrical properties of NiO, making them highly applicable for optoelectronic devices.

Herein, we are reporting, for the first time, a microwave-assisted synthesis of lead iodide (PbI2) nanosheets (NSs) with codoping of Zn and Mn, confirmed by SEM/EDX. In the co-doping Mn concentration was kept at a constant level (i.e. 15 %) while Zn concentration was varied from 1 wt.% to 10 wt.%. The morphological analysis confirming presence of the dopant was done through SEM/EDX. The single phase and polytypic nature of NSs were established by XRD and FT-Raman examinations. Homogeneous doping of Mn and Zn in prepared PbI2 NSs was confirmed by SEM mapping analysis. The dielectric and electrical properties were measured by preparing a compact pellet of NSs at 49820 Pa pressure. The dielectric constant and electrical conductivity were enhanced by Zn:Mn co-doping in PbI2. The radiation activity was tested by cesium-137 (137Cs) radioactive source and its increase resulting from the doping was observed. The enhanced properties suggest that the prepared NSs may be useful in electro-optic and radiation detection device applications.

High-quality thin film-based photodetectors containing praseodymium doped cadmium sulfide (Pr:CdS) were fabricated through spray pyrolysis and studied for various opto-electrical applications. Field emission electron microscopy (FE-SEM) revealed that the prepared films were highly compacted with an extremely fine nanostructure without any pinhole or crack. X-ray diffraction and FT-Raman spectroscopy studies confirmed the single hexagonal phase of all the films. The crystallite size was found to lie between 19 and 32 nm. Optical spectroscopy revealed that the fabricated films have low absorbance and high transmittance (in range of 70–80%). The energy gap was found to lie in the range of 2.40–2.44 eV. The PL spectra contained an intense green emission band at ~531 ± 5 nm (2.33 eV), and its intensity was enhanced by increasing the Pr doping content in CdS. The dark and photo currents of CdS increased by approximately 950 and 42 times, respectively with the addition of 5.0 wt% Pr. The responsivity (R) and specific detectivity (D*) were remarkably enhanced to 2.71 AW-1 and 6.9 × 1011 Jones, respectively, for the 5.0 wt% Pr:CdS film. The external quantum efficiency (EQE) of 5 wt% Pr:CdS films was 43 times that of pure CdS films, and the on/off ratio was 3.95 × 102 for 5.0 wt% Pr:CdS film. Its high R, D*, and EQE values, and photo-switching behavior make Pr:CdS a good contender for high quality photodetector 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.

Good quality cadmium sulfide (CdS) thin films were deposited on substrates of glass with different Cu concentrations using a sophisticated spray pyrolysis technique. Structural study confirms the formation of hexagonal phase CdS films with good crystallinity. The crystallite size was calculated to be in range from 19 to 21 nm and the texture coefficient was found to be higher along (110) plane for 1.0 wt.% CdS:Cu film. Further confirmation of hexagonal phase with improved crystallinity was approved by vibrational spectroscopy analysis. SEM mapping/EDX spectra shows the homogeneous presence of Cu in final film. SEM signify the nanostructured thin films fabrication with nanocrystallites formations. The optical transparency of fabricated films was noticed in range of 60 to 80%. The absorption and refractive indices values were estimated and found in range of 0.03 to 0.24, 1 to 3. The direct energy gap was noticed to reduce from 2.44 to 2. 31 eV by Cu doping. The PL spectra contains a single peak in range from 502 to 532 nm for pure and Cu doped CdS films, which is assigned to green emission and noted to be shifted towards lower wavelength. Dielectric constant, loss. loss tangent and conductivity were also determined and discussed. Moreover, the third order nonlinear susceptibility and nonlinear refractive index were calculated and found to be of high orders. The optical limiting study was also carried and shows noticeable effect of Cu doping. All results suggest that the CdS:Cu films are of good quality hence can be employed in opto-nonlinear devices.

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.

Herein, we have facilely synthesized high purity ZnO nanoparticles by flash combustion technique in presence of different citric acid (CA) content. X-ray diffraction study rules out the existence of any extra phase except single hexagonal phase of ZnO. Further, crystallite size, dislocation density and strain values were estimated, and the crystallite size was found to be reduced from 20to 10 nm with rising the concentration of CA. Vibrational study also confirm the single phase in accordance with XRD results and revealed that the modes of vibration are slightly shifted owing to quantum size effect and relaxed nanostructure formation. To confirm the purity of synthesized ZnO the energy dispersive X-ray spectroscopy was carried out which confirm the high purity of synthesized products. Spherical nanoparticles (SNPs) morphology was confirmed through scanning electron microscopy and the size is reduced with raising the concentration of CA. TEM study was also carried out which clearly shows the formation of spherical nanoparticles (SNPs) and the mean size is around 10 nm for 1 g CA:ZnO and

Herein, novel Ag-doped PbS (Ag:PbS) nanoparticles (NPs) were synthesized via a facile and rapid microwave route. Field emission scanning electron microscopy (FESEM)/energy-dispersive X-ray (EDX) spectroscopy were employed to confirm the homogeneous doping of Ag in PbS. The transmission electron microscopy (TEM) exposed that the PbS NPs were fully encapsulated with Ag. X-ray diffraction (XRD) analysis revealed that all the samples possessed cubic crystal structures whereas the peak positions for the Ag:PbS were slightly shifted towards lower angle compared to pure PbS, further confirm the Ag doping in NPs. Fourier-transform Raman (FT-Raman) spectra also confirmed the phase and doping of Ag in PbS NPs. The grain sizes of the synthesized NPs were found to be in the range of 15–40 nm while calculated crystallite sizes of these samples were in the range of 18–26 nm. The zeta potential for 5.0 wt% Ag:PbS NPs was found to be approximately 10 times higher than that for pure PbS NPs, signifying the high stability of the doped NPs in aqueous media. The optical band gap of Ag:PbS NPs were evaluated from diffused reflectance spectra and found to be in range of 1.95–2.51 eV; increases with Ag doping. The quenching in photoluminescence (PL) intensity was observed with the increase of Ag doping concentration attributed to the charge transfer between Ag and PbS. Moreover, Ag doping also improve the electrical and dielectric properties of PbS NPs. Finally, optoelectrical properties of synthesized materials were investigated under 633 nm laser-light illumination to determine their applicability as visible-light photodetectors. It was found that the Ag doped PbS NPs exhibited enhanced photodetector figures of merit compared to the pure PbS NPs.

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

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.

The single-layered Germanium sulfide exhibits interesting optoelectronic properties however the indirect bandgap hinders its practical applications for nanoscale optoelectronic and photovoltaic devices. Herein, we report two direct bandgap polymorphs of single-layered GeS (δ-GeS and e-GeS) and explore their optoelectronic properties using the density functional theory based computational approaches. The indirect bandgap of the intrinsic GeS monolayer (α-GeS) calculated in present study amounts to 0.76 eV, whereas the direct bandgap energies for δ- and e-derivatives of GeS have been recorded as 1.93 and 2.10 eV respectively. The optical spectra of these monolayers demonstrated a high degree of anisotropy and significantly different optical absorption, reflection, and refraction coefficients were seen in the x- and y-directions. They exhibited different plasmons energies along x- and y-directions which reveal the GeS monolayers as potential polarizers of electromagnetic radiations. Moreover, these monolayers demonstrated exceptionally large optical absorption spanning over a wide range of electromagnetic spectrum. The absorption coefficients were recorded typically larger along y-axis than x-axis. The designed direct bandgap monolayers are believed to overcome the major hurdles of single-layered GeS for nanoscale optoelectronic applications.

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

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

Synthesis of NiO nanostructures in presence of different concentrations of citric acid (CA) was achieved through flash combustion technique. The NiO nanostructures formation was confirmed through X-ray diffraction analysis. At low concentrations of CA no extra peak was observed in XRD patterns, however when the CA concentration was raised to 5 and 10 g, two new extra peaks appeared at 44.6° and 51.9° which may be attributed to the presence of C. The crystallite size was noticed to reduce from 29 to 18 nm with increase in the CA concentration. All observed Raman bands were noticed to be shifted owing to the quantum size effect. EDX and SEM mapping confirm the existence of C. SEM images confirm the cubic nanocrystalline morphology for 0.5 g CA:NiO, however with increasing CA concentration a drastic change in morphology, i.e. from nanocrystals to extended nanosheets, was observed. The energy gap values were determined using Kubelka-Munk theory and found in range of 3.5–4.0 eV. An additional energy gap ∼2 eV was also noticed at higher CA concentration. The values of relative permittivity, e r ′ , were found in the range of 18–110 for CA concentration upto 5g, however, at 10.0 g CA its value was found to be order of 104 at 2 × 105 Hz.

Different concentrations of Pt doped PbS nanostructures synthesis has been attained facilely by chemical route. X-ray diffraction (XRD) and FT-Raman spectroscopy analyses confirms the structure. After close inspection and indexing of diffraction peaks, the absence of additional peak owing to any contamination or free Pt in final products was confirmed. XRD data was further used to evaluate the lattice constants, crystallite size, density and strain to see the effect of Pt on these. Calculated lattice parameters confirm the single cubic phase, which was in correlation with vibrational modes analysis. The crystallite size was calculated in range from 9 to 11 nm. For further confirmation of Pt doping and its homogeneity in final product the EDX/SEM mapping was carried out and approved the homogeneous presence of Pt in PbS. SEM study revealed that the morphology is changing from nanoparticles (NPs) to nanosheets (NSs). Diffused reflectance spectra (DRS) were measured for powdered samples and energy gap was estimated up to 1.32 eV. Photoluminescence spectra was recorded and shows an intense green and broad red emission bands at 518 and 700 nm, correspondingly. The values of dielectric constant are found in range of 18–28. Total ac electrical conductivity is rising with applied frequency. The energy gap value suggest the application of synthesized Pt:PbS NPs and NSs in solar cell.

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.

La-doped SnO2 thin films (1, 2.5, 5.0, 7.5 and 10%) have been coated on FTO substrates by a sol-gel spin coating technique. XRD studies confirms the (100) orientation of all prepared films of polycrystalline nature. Vibrational modes confirm the fabrication of single phase SnO2 films. EDX/SEM mapping confirms the presence of La in SnO2 films. AFM reveals the grain size in range of 17–82 nm along with RMS roughness in 13 and 38 nm. The direct band gap values of pure and La doped SnO2 thin films are varying between 4.15 and 3.95 eV. The refractive index (n) and absorption index (k) values were found to be reducing below 5% La doping and showed an increasing tendency beyond 5% doping. Further, the investigated values ( χ 1 ) , ( χ 3 ) and n 2 were found in the range of 0.032–47, 1.5 × 10−8 to 8 × 10−4 esu and 2.3 × 10−7 to 1.2 × 10−3, respectively.

Dimensionality reduction has been proved as a feasible route to enhance the performance of thermoelectric materials for renewable energy applications. In this article, we investigate the effect of dimensions reduction on thermoelectric properties of GeSe using the density functional theory and Boltzmann transport theory based first-principles approaches. These investigations have been carried out for bulk (3D) and three polymorphs of single-layered (2D) GeSe (such as α-GeSe, β-GeSe, and γ-GeSe). Calculations of energetic stability demonstrated the 2D-GeSe as stable as the 3D-GeSe. The arrangement of bands within the electronic band structures of 3D and 2D GeSe showed them as indirect bandgap semiconductors. The β-GeSe and γ-GeSe exhibited wider energy bandgap and consequently large Seebeck coefficients than the 3D-GeSe and α-GeSe. The reduction in structural dimensions stimulated a sharp increase in electrical conductivity and Seebeck coefficient (particularly for β-GeSe and γ-GeSe) which has resulted in large power factor. The room-temperature thermoelectric figure of merit (ZT) of 3D-GeSe, α-GeSe, β-GeSe, and γ-GeSe of magnitude 1.02, 0.83, 1.00, and 1.10 respectively have typically broken the benchmark value of ZT ≈ 1. The ZT of these materials is sensitive to change in temperature and has been recorded as large as 1.72 for γ-GeSe at a low temperature of 150 K. The large power factors and ZT of single-layered GeSe reveal the dimensionality reduction as a feasible approach for enhancing the performance of thermoelectric materials for renewable energy applications.

Undoped and rare earth Neodymium (Nd) doped cuprous oxide (Cu2O) thin films were prepared by electrodeposition method. The prepared film's structural, morphological, optical and photosensitive properties were analyzed by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, ultra violet-visible and I-V measurements. The fabricated Cu2O:Nd films exhibited polycrystalline nature with cubic crystal system, and favorably grown along (111) orientation. Crystallite size was decreased from 56 nm to 30 nm with Nd concentrations. Raman spectrum confirmed the Cu2O phase of the prepared films. The morphological analysis showed pyramidal shaped particles for the undoped Cu2O thin film. The energy gap was reduced from 2.04 eV to 1.89 eV as Nd doping level was increased. From photoluminescence spectrum a high intense peak was observed at 619 nm which confirms the optical quality of Cu2O phase. The dielectric constant was increased by increasing the Nd doping concentration from 0 to 5%. In photosensitivity analysis an increase of photo response with respect to illuminated current was observed.

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.

Improving the performance of thermoelectric materials for clean energy production via structural manipulation is considered as an effective route to advanced thermoelectrics. Here, we report the im...

The low-cost and nontoxic single-layered SnS has been recently predicted as a promising material for cutting-edge nanoscale optoelectronic and photovoltaic applications beyond the graphene and phosphorene. In this article, we assess the optoelectronic properties of five derivatives of single-layered SnS (such as α-, β-, γ-, δ-, and e-SnS) using first-principles calculations. While the single-layered SnS (α-SnS) itself is an indirect bandgap semiconductor, its derivative δ-SnS demonstrated a direct bandgap and e-SnS a nearly direct bandgap which makes them promising over phosphorene. This new class of monolayers exhibits structural anisotropy along diagonal components of magnitude 0.098, 0, 0.24, 0.007, and 0.036 for α-SnS, β-SnS, γ-SnS, δ-SnS, and e-SnS respectively. The large degree of in-plane anisotropy has generated different bands dispersion and effective mass of charge carriers along the 100- and 010- directions that evolve interesting effects on their optoelectronic properties. The optical spectra of the SnS monolayers have been found significantly different along the x- and y-axis. Investigations of the excitonic binding energies indicated that the designed monolayers exhibit thermally stable excitons. The onset optical absorption energies occur over a wide range of the visible part of the electromagnetic spectrum which is appealing applications in optoelectronic and photovoltaic devices. The refractive indices and reflectivity spectra have been found significantly different along x- and y-directions that may find suitable applications in optical polarizers, filters, and shields against UV radiations. The present study is believed to provide useful guidance for the applications of SnS monolayers (δ-, and e-SnS in particular) in direction-dependent nanoscale optoelectronic and photovoltaic devices beyond phosphorene and graphene.

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

For cost-effective fabrication of pure and 0.2, 0.4, 0.6 and 0.8 wt% Dy doped PbI2 thin films on FTO substrate using spin coating process was developed. First, we synthesized the pure and different concentrations of Dy doped PbI2 by a facile microwave route (within 15 min) at 700W power. Single phase and highly oriented films were fabricated on FTO substrate was confirmed by X-ray diffraction analysis. Further, lattice constant, crystallite size, dislocation density, lattice strain, number of unit cells, texture coefficients etc. were evaluated. Lattice constants were observed in good agreement with JCPDS#7–0235. The values of crystallite size were found in the range of 14 nm–28 nm. Moreover, FT-Raman study also confirms the single phase and high crystallinity of the fabricated films. Surface morphology was analyzed by SEM, as nanorods shape and nanoparticles; and grains size was in the range of 25–40 nm. Robust optical, nonlinear and optical limiting studies were carried out to have deep insight on key properties of films for future device applications. The optical energy gap was found in the range of 2.35–2.65 eV. The values of χ(1), χ(3) and n(2) were found in the range of 0.35–1.4, 0.023 to 8.15 ( × 10−10) esu and 0.0052 to 6.94 ( × 10−9), respectively. The optical limiting values were found in the range of 10.5–7.7 mW (532 nm CW laser) and 208.2–134.5 μW (632.8 nm CW laser) for all deposited films.

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.

Synthesis of pure and 0.1 to 5 wt.% Gd-doped CdS nanoparticles (NPs) was achieved through a modified domestic microwave-assisted route in a short timespan at 700 W power. The formation of hexagonal CdS NPs was verified via X-ray diffraction analysis, and no structural variation was observed except for lattice variation. The size of the crystallites (D), dislocation concentration, and lattice strain were calculated, and the D was in the range of 3–6 nm. Fourier transform-Raman analysis confirmed the presence of 1LO, 2LO, and 3LO modes at 294.76, 590, and 890 cm−1, respectively, in all the synthesized nanostructures, with minute variations in their positions due to doping; however, no new mode was observed. The position of the vibration modes was red shifted compared to that of the bulk material, indicating a confinement effect. Scanning electron microscopy (SEM) mapping/energy-dispersive X-ray spectroscopy revealed homogeneous doping of Gd and the presence of all the constituents in the final products. The morphology of the synthesized materials was tested via field-emission SEM, which revealed spherical NPs with small dimensions. Additionally, high-resolution transmission electron microscopy was performed to visualize the shape and size of the prepared 0.1% Gd:CdS NPs. The energy gap was calculated using the Kubelka–Munk theory and found to be in the range of 2.31–2.41 eV. The photoluminescence emission spectra exhibited two green emission peaks at 516 ± 2 nm and 555 ± 2 nm and showed the reduction of defects with Gd doping in terms of intensity quenching. The dielectric constant ( e ' ), loss, and alternating-current electrical properties were studied in the high-frequency range. The values of e ' were in the range of 17–27. An enhancement of these values was observed for CdS when it was doped with Gd. The electrical conductivity exhibited frequency power law behavior.

In this study, synthesis of pure and Cu doped lead sulfide (PbS) nanoparticles was facilely achieved. The good crystalline nature of the nanoparticles was confirmed via X-ray diffraction (XRD) analysis. Specifically, XRD data was also used to estimate the diffraction planes, lattice constants, size of crystallites, density of dislocations, and strain produced in the lattice. The XRD pattern was indexed after identifying the diffraction planes. The crystallite size was estimated to be in the range of 18–23 nm. The absence of any additional vibrational mode in Raman spectra was observed, and this confirmed the purity of PbS even at a higher Cu doping level. However, the vibrational modes exhibited some shift towards lower wavenumbers. Low dimension nanoparticles morphology and presence of Cu were investigated via scanning electron microscope/ Energy Dispersive X-Ray (SEM/EDX) analysis. Additionally, homogeneous Cu doping in final product was observed in an EDX elemental mapping image. Optical measurements were performed by recording diffused reflectance. Both direct energy gap values were estimated in the range of 1.15–1.50 eV, and this significantly exceeded that of the bulk (i.e., 0.41 eV). Dielectric and J-V electrical measurements were performed. The dc conductivity and mobility values were observed extremely high for 2.5% Cu doped PbS NPs [which correspond to 2.48 × 10−5 S/cm and 1.3 × 104 cm2/(V s)] when compared to those of pure and other doped PbS NPs.

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

Linear and nonlinear optical properties of ammonium dihydrogen phosphate (ADP, NH4H2PO4) crystal are tailored by employing environmental growth in presence of urea and explore its applicability for photonic device applications. The structural parameters of pure and urea influenced ADP crystal has been determined by single crystal X-ray diffraction technique. The energy dispersive spectroscopic analysis has been employed to examine the constituent elements of grown crystal. The consequence of urea surrounding on optical transparency of ADP crystal has been examined within 200–1100 nm by means of UV–vis spectral analysis. The enhancing effect of urea on second harmonic generation (SHG) efficiency of ADP crystal has been determined using the Kurtz-Perry test. He-Ne laser assisted Z-scan technique has been employed to assess the third order nonlinear optical (TONLO) properties of urea affected ADP crystal at 632.8 nm. The magnitude of TONLO parameters (nonlinear refraction (n2), nonlinear absorption (β) and cubic susceptibility (χ3)) has been evaluated using the Z-scan transmittance data. The thermal stability of urea influenced ADP crystal has been experimentally evaluated by means of simultaneous thermogravimetric and differential thermal analysis.

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

The current investigation is aimed to explore the enhancing effect of increasing concentration of amino acid L-alanine (LA) on decisive optical traits of zinc thiourea chloride (ZTC) crystal. The most commercial slow solvent evaporation technique has been adapted to grow pure and LA influenced ZTC crystals at room temperature. The powder X-ray diffraction analysis has been carried out to determine the crystallographic data and analyze the crystalline phase and purity of pure and LA influenced ZTC crystals. The constituent elements of grown crystals have been evaluated by means of energy dispersive spectroscopic technique. The influence of LA on optical transparency of ZTC crystal in range of 190–1000 nm has been ascertained by means of UV-visible spectral analysis. The optical band gap of grown crystals has been evaluated using the transmittance data to discuss the technological impetus of grown crystals for optical devices. The Kurtz-Perry test has been performed to determine the positive impact of organic ligand of LA on second harmonic generation (SHG) efficiency of ZTC crystals. The SHG efficiency of LA influenced ZTC crystal is found to be remarkably higher than pure ZTC and potassium dihydrogen phosphate crystal materials. The effect of LA on photoluminescence nature of ZTC crystal has been investigated in the range of visible region. The impact of LA on temperature dependent dielectric response of ZTC crystal has been investigated within the range of 30–90 °C.

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.

Herein, we report a facile, cost-effective, solution processed fabrication method for pure and lanthanum (La3+) doped lead iodide (PbI2) thin films and investigated structural, optical, dielectric and electrical properties. Synthesis of PbI2 was confirmed by X-ray diffraction (XRD) and FT-Raman spectroscopy analyses. The fabricated films were grown along (001) plane, with crystallite size in the range of 12–14 nm and observed that crystallinity increases and defects decreases with the increase of La doping concentration. The morphology of fabricated films was observed to be spherical nanoparticles assembled nanosheets, distributed uniformly throughout the films. Moreover, homogeneous La doping in PbI2 was seen via EDX elemental mapping image. Optical band gap was calculated from Ultra violet–visible–near infrared (UV–Vis–NIR) spectra. The band gap of pure PbI2 film was noticed ∼2.44 eV which increase to 2.63 eV for 3% La3+ doped film. Absorption index, refractive index and dielectric constant values were calculated from optical data and found to be strongly dependent on incident photon energy and all parameters show higher values for La doped PbI2 films. I-V characteristics of pure and La-doped PbI2 thin films were carried out in the device configuration viz. FTO/PbI2 (or La-doped PbI2)/Au at room temperature. I-V curve for the pure PbI2 films shows the ohmic behavior while La doped PbI2 films shows non ohmic behavior attributed to space charge limited current. The electrical resistivity values for pure PbI2 film is found to be very high about 1.8 × 1011 Ω-cm.

Highly stable Rose Bengal (RsB) organic semiconductor thin films were deposited on glass substrates with different thicknesses ranging from 95 to 325 nm. Optical transmission, reflection, and absorption studies were employed to analyze various optical constants. Refractive index and extinction coefficient values were attained using Kramers-Kronig calculations from the reflectance data. Dielectric constant, loss and dissipation factor were studied. Third-order nonlinear optical susceptibility and refractive index values were estimated using linear refractive index and absorption coefficient data for RsB films and studied their properties in nonlinear media. Optical limiting characteristics are found to be enhanced by increasing the thicknesses of films. The studied films can be used to limit the laser power of wavelengths 632 nm and 532 nm as an optical limiting material. The present work suggests that film of RsB is a promising candidate for wide-scale optoelectronic applications including IR pass filter, laser power attenuation, and selective CUT-OFF laser filters in the wavelength range 490–595 nm.

Different concentrations of N (0, 1, 3 and 5 wt.%) added ZnO thin films were primed using spin coater. X-ray diffraction (XRD) patterns confirm the preferred growth orientation of all films along (0 0 2) plane, however, ITO has dominant features owing to low thickness of the films. XRD along with vibrational spectroscopy confirms the single hexagonal phase of ZnO. The crystallite size evaluated from Scherrer's equation increased with increase in N-doping concentrations and is found to lie in the range of 25–36 nm. The increased crystallite size reduces the dislocation density which confirms the reduction of defects in the films. The dislocation density (δ) is found to be 1.569, 1.369, 0.984, and 0.965 for 0, 1, 3 and 5 wt.% N doped ZnO films. N doping in ZnO was confirmed by EDX analysis and its homogeneous distribution was further confirmed by SEM mapping. AFM study confirms the formation of spherical nanoparticles whose size increase with increase in N doping, validating the XRD results. The films are found to have ∼80% transparency which is quite impressive from window layer application point of view. Absorption edge is found to be red shifted owing to N doping, indicating a reduction in energy gap. Hence energy gap was evaluated using Tauc's relation and is found to reduce from 3.43 to 3.14 eV (ΔE = 0.29 eV) with in content of N-doping. The absorption index, refractive index, real and imaginary dielectric constants were also estimated. The values of χ(1) and χ 3 are estimated to be in range of 0.3–9 and 1.0 × 10−11 - 1.0 × 10−8, respectively. The Nanocrystalline films with spherical nanocrystallites, high optical transparency and non-linear properties recommend their application in opto-electronic technology.