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This research communication presents a rapid and facile microwave-assisted synthesis of single crystalline nanosheets (SCNSs) of hexagonal lead iodide ( PbI 2 ) decorated with Au nanoparticles, a potential optoelectronics material. Homogeneous low dimensional AuNP decoration in PbI 2 resulted in a new absorption band at ~604 nm and a shift in band gap from 3.23 to 3.00 eV. The significant enhancement of photoluminescent (PL) intensity observed in the AuNP-PbI 2 SCNSs is attributed to the coupling of the localized surface plasmon resonanzce of AuNP leading to improved excitation and emission rates of PbI 2 -SCNSs in the region of the localized electromagnetic field. The Au-PbI 2 SCNSs display a compelling increment in photoconductivity, and its fabricated photodetector showed a stable and switchable photo-response. Due to ease of synthesis and enhanced photoconductivity along with appealing PL features, Au-PbI 2 SCNS has the potential to be used as a material of choice when fabricating an optoelectronic devices of high performance.

The melt-quenching method has been used to fabricate Na 2 B 4 O 7 - CdO glass system. The XRD diffractometer procedure was used to check the status of these samples. Inter-ionic distance ( R i ) between Cd–Cd, Polaron radius r p , and inter-nuclear distance r i reduced with Cd content due to reducing molar volume. Ionicity I b decreased and covalent glass character increased as CdO in the glass matrix increases. As the CdO contents increase, the values of T g , T c , and T P have been increased. All expected phases are displayed in the XRD patterns. SEM has studied the morphology of the vitreous ceramic. It has been noted that the velocities and elastic modulus of glass-ceramics samples are increased. The structural nature of the developed phase was monitored in spectroscopic FT-IR investigations of the glass-ceramic samples. Mass attenuation Coefficient ( μ/ρ ) increases with CdO-content increase. The Z eff values increase gradually at higher energy because of X-ray K -edges. Hence, the increase in CdO content can be developed the γ -radiation. According to our data, G7 is the best sample for shielding properties.

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.

Using experimental and computational techniques, a comparative study of electro-optical properties for glycine glycinium picrate (GGP) and glycinium picrate (GP) compounds has been performed. The single crystal of GGP has been grown using slow evaporation technique that was further subjected to experimental characterization of its electro-optical properties. The good optical transparency and mechanical strength at micro level was confirmed from optical and nanoindentation measurements using the Oliver–Pharr method of the grown single crystals. Differential scanning calorimetric (DSC) analysis was done to probe the thermal stability of the grown single crystals. Using the density functional theory (DFT) methods, we have not only investigated the GGP but also proposed GP molecule. Additionally, we have shed light on the molecular geometries, infrared and Raman spectra, linear and nonlinear optical properties of both GGP and GP at molecular level. The time dependent DFT (TD-DFT) approach was adopted to calculate the excitation energies of the molecules in different phases including gas, water, acetone, cyclohexane and chloroform as well. For GGP, its wavelength of maximum absorption is calculated to be ∼390 nm at B3LYP/6-31G∗ level of theory. The calculated amplitudes of first hyperpolarizability (βtot) for GGP and GP are found to be 712 and 970 a. u., respectively, which are about 16 and 23 times larger than that of the urea molecule (a prototype NLO molecule). Thus the present study not only brings to limelight the optical and nonlinear optical properties of GGP but also sheds light on the possible potential of GP as new NLO molecule.

Electrical and switching property of amorphous defect chalcopyrite Zn[Ga.sub.2][Te.sub.4] thin films prepared by thermal evaporation technique has been studied. The elemental chemical compositions of the prepared bulk as well as the as-deposited film were determined by means of energy dispersive X-ray spectrometry. X-ray diffraction pattern revealed that the powder compound is polycrystalline and the as-deposited and the annealed films at [t.sub.a] ≤ 548 K have the amorphous phase, while that the annealed at t ≥ 573 K are polycrystalline with a single phase of a defect chalcopyrite structure similar to that of the synthesized material. The great advantage of this material is the capability to appear in two different phases, the amorphous and the crystalline phases, with rather different electrical properties. Both dynamic and static I-V characteristics and the switching phenomenon at 601 nm are investigated. The threshold switching mechanism was explained by a thermal model of switching, i.e., joule heating with an electrically conducting channel. Zn[Ga.sub.2][Te.sub.4] is good candidate in phase change memory device.

NiO is an excellent contender for smart windows, electrochemical super capacitor and dye sensitized photocathode. Hence, thin films of NiO with different concentrations (1, 3, 5 and 7 wt%) of Cr doping has been fabricated by a facile and low cost technique. The analysis of effect of Cr concentrations on structural, vibrational, morphological, optical and nonlinear optical properties has been studied. X-ray diffraction study confirms that the fabricated films are of polycrystalline nature with cubic phase. The determination of structural parameters such as crystallite size, dislocation density, lattice strain and number of crystallites per unit area was done. The presence of Cr doping in NiO was confirmed by EDX analysis. The vibrational modes were studied by FT-Raman analysis. AFM topography was recorded for pure and Cr doped NiO films. The crystallite/grain size was found to be in the range of 36–40 nm (from X-ray) and 6–12 nm (from AFM). High optical transparency was observed from visible to near infrared region for all the deposited films which is ~ 70 to 85%. The direct and indirect optical band gap were calculated and the direct band gap is found in the range of 3.85–3.78 eV. The optical constants like linear and nonlinear refractive index ( n 2 ) , optical dielectric constant and loss, optical and electrical conductivity, third order nonlinear optical susceptibility ( χ 3 ) were calculated from reflectance and absorbance data. The values of n 2 and χ 3 are found to be of order of 10 −7 and 10 −9 esu, respectively.

Laser Induced Breakdown Spectroscopy (LIBS) technique has been applied to study the annealing effect of Al-Ge alloy at 150, 175, 240, 280, 325 °C. LIBS spectra of all samples prepared at these annealing temperatures were recorded. The signal intensity of the Al and Ge spectral lines increases with increase in annealing temperature. This increase in the signal intensity is due to structural modification of Al-Ge sheets surface with annealing temperatures. This variation in intensity verifies the assessment of annealed materials which can be performed with LIBS technique.

Casting technique was used to prepare nanocomposites of polyvinyl alcohol (PVA) and graphene oxide (GO). GO has been set up by Hummer’s method and characterized by SEM and X-ray spectroscopy. Samples have been designed to contain a different weight percent of GO as follows: (0.370, 0.926, 1.852, 2.778, 3.704, 9.259 wt%) inside PVA matrix under the homogenous ultrasonic system to have a highly dispersed GO in PVA matrix. The nanocomposites were described and analyzed by utilizing different methods such as UV–Vis–NIR, dielectric studies at room temperature and optical limiting properties. It is shown that the influence of the nanofiller leads to the increase in the absorption values while diminishing the optical band gap of both direct and indirect transition. The dielectric constant ( ε ′) and the dielectric loss ( ε ″) were studied within the frequency range from 3 kHz to 10 MHz and were found to be depending on the GO contents. The conduction mechanism for the studied samples can be described by the correlated barrier hopping. PVA/GO nanocomposites showed good optical limiting properties. The synthesized GO-doped PAV can be used in electronic and optoelectronic applications especially in battery electrolyte and dye-sensitized solar cells.

X-ray diffraction pattern and AFM results confirm the nanostructure of p-Zn[Ga.sub.2][Se.sub.4]/n-Si. The unit cell lattice parameters, the crystallite size L, the dislocation density δ, and the main internal strain e were calculated. The temperature and frequency-dependent electrical characteristics of the Al/p-Zn[Ga.sub.2][Se.sub.4]/n-Si/Al heterojunction diode (HJD) have been investigated to determine the interface states which are responsible for the non-ideal behavior of the characteristics of the diode. The capacitance-voltage (C-V), conductance-voltage (G-V), and series resistance-voltage ([R.sub.s]-V) characteristics of the diode have been analyzed in the frequency range of 5 kHz-1 MHz and temperature range of 303-423 K. The interfaces states of the diode were determined using conductance-voltage technique. The interface state density profile for the diode was obtained as a function of temperature and frequency. The values of the built-in potential [V.sub.bi], the doping concentration [N.sub.d] and the barrier height [φ.sub.b(C-V)] of the diode were calculated at different temperatures and frequencies. Our experimental results revealed that both the series resistance and interface state density values must be taken into account in studying the impedance spectroscopy of HJD to stand up their performance for electronic applications characteristics.

The spray pyrolysis as a simple and cost-effective thin film deposition technique was used to obtain transparent conductive oxides (TCOs) thin films of SnO 2 and F-doped SnO 2 on soda-lime glass substrates at 500 °C. The surface morphology and average crystallite size of the deposited TCOs thin films were investigated by the field emission scanning electron microscope and X-ray diffraction technique. The crystalline grains of the as deposited films preferentially oriented along (101) plane according to the tetragonal crystal structure of SnO 2 . The tetragonal phase of SnO 2 for the deposited films has been confirmed from the fundamental peaks of Raman spectrum. The optical constants like optical band gap, refractive index, and absorption coefficient for SnO 2 and F-doped SnO 2 films have been evaluated on the basis of Swanepoel model depending on the transmission spectra for the deposited films. All TCOs films under study have direct optical band gap its value increased slightly with the F doping level. The figure of merit of the thin films under study was calculated to check the availability of the films as TCOs in thin film solar cell applications. The charge carrier concentration and Hall mobility of the thin films under investigation also have been determined from the Hall measurements. The effect of γ-irradiation with distinct doses on the transmittance, optical band gap, and crystal structure also has been studied for the deposited films.