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•Development of ZnO:Co thin films with improved optical and electrical properties is reported.•The band gap of the films was found to between 3.32 and 3.43 eV for 0, 2, 4, 6 and 8% Co ...concentration respectively.•Photoluminescence intensity was high for 4% Co doped ZnO sample with near band edge (NBE) emission at 392 nm.•Responsivity (R), External Quantum Efficiency (EQE) and Detectivity (D*) were carried out and found to be 9.35 × 10−1 AW−1, 218% and 9.32 × 1010 Jones respectively for ZnO:Co 4% sample.•4% Co doping content noticeably enhanced the photodetection performance of ZnO NSs films.
Co doped ZnO thin films were developed by cost effective Successive ionic layer adsorption and reaction (SILAR) method. The Co doping concentration was varied from 0, 2, 4, 6 and 8% in the ZnO and their corresponding physical, morphological, structural, optical, and photo sensing properties were carried out. The XRD studies confirmed the phase purity, structure of ZnO lattice as hexagonal wurtzite and the crystallite size increases from 43 to 52 nm due to the substitutional replacement of Co doping concentration. The morphology of the thin films by FESEM revealed that inclusion of Co over the ZnO lattice doesn’t affect the morphology but increment of grain size which is desired for UV Photo detectors. From the optical studies, maximum absorbance in UV region and minimum optical bandgap for ZnO:Co4% sample was observed. Photoluminescence intensity was high for 4% Co doped ZnO sample with near band edge (NBE) emission at 392 nm. Responsivity (R), External Quantum Efficiency (EQE) and Detectivity (D*) were carried out and found to be 9.35 × 10−1 AW−1, 218% and 9.32 × 1010 Jones respectively for ZnO:Co 4% sample. The entire work concludes that inclusion of 4% Co in the ZnO thin film made it as a potential candidate for photo sensing applications in UV region.
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The current work is to highlight the fundamental acumen about the molecular structure, photophysical and static first hyperpolarizability (β) of L-Histidinium 2-nitrobenzoate (LH2NB) ...organic molecule for the first time. Hartree–Fock (HF) and density functional theory (DFT) has been applied using different functional at 6-31G∗∗ basis set for the first time. The strong correlation has been observed between experimental and theoretical vibrational spectra. TD-DFT method has been used at different levels of theory to study the UV–Visible spectra. The analysis of HOMO and LUMO was done to explain the charge interaction taking place within the molecule and the energy gap was evaluated. The value of dipole moment is found to be lower in excited state than ground state as calculated from all applied methods. The value of total static first hyperpolarizability was found to be 7.447×10−30esu at B3LYP/6-31G∗∗ level of theory, which is about 20 times higher than urea molecule. The current results indicate that the studied molecule may be a decent applicant for opto-electronic applications.
Abstract
In recent years, there has been an increase in demand for inexpensive biowaste-derived photocatalysts for the degradation of hazardous dyes and pharmacological drugs. Here, we developed ...eggshell derived hydroxyapatite nanoparticles entrenched on two-dimensional g-C
3
N
4
nanosheets. The structural, morphological and photophysical behavior of the materials is confirmed through various analytical techniques. The photocatalytic performance of the highly efficient HAp/gC
3
N
4
photocatalyst is evaluated against methylene blue (MB) and doxycycline drug contaminates under UV–visible light exposure. The HAp/gC
3
N
4
photocatalyst exhibit excellent photocatalytic performance for MB dye (93.69%) and doxycycline drug (83.08%) compared to bare HAp and g-C
3
N
4
nanosheets. The ultimate point to note is that the HAp/gC
3
N
4
photocatalyst was recycled in four consecutive cycles without any degradation performance. Superoxide radicals play an important role in degradation performance, which has been confirmed by scavenger experiments. Therefore, the biowaste-derived HAp combined with gC
3
N
4
nanosheets is a promising photocatalyst for the degradation of hazardous dyes and pharmacological drug wastes.
Herein, the optoelectrical investigation of cadmium zinc telluride (CZT) and indium (In) doped CZT (InCZT) single crystals-based photodetectors have been demonstrated. The grown crystals were ...configured into photodetector devices and recorded the current-voltage (I-V) and current-time (I-t) characteristics under different illumination intensities. It has been observed that the photocurrent generation mechanism in both photodetector devices is dominantly driven by a photogating effect. The CZT photodetector exhibits stable and reversible device performances to 632 nm light, including a promotable responsivity of 0.38 AW
, a high photoswitch ratio of 152, specific detectivity of 6.30 × 10
Jones, and fast switching time (rise time of 210 ms and decay time of 150 ms). When doped with In, the responsivity of device increases to 0.50 AW
, photoswitch ratio decrease to 10, specific detectivity decrease to 1.80 × 10
Jones, rise time decrease to 140 ms and decay time increase to 200 ms. Moreover, these devices show a very high external quantum efficiency of 200% for CZT and 250% for InCZT. These results demonstrate that the CZT based crystals have great potential for visible light photodetector applications.
This paper is focused on optical nonlinearity in CdS nanostructured thin films, which was reviewed comprehensively and discussed in detail along with future perspective. Due to third harmonic ...generation in CdS materials on exposed to highly intense light that is significant feature to develop modern photonics devices. CdS chalcogenide semiconductor binary compound is one of the most particularly promising candidate for nonlinear optical applications due to their enhanced nonlinear optical properties in thin films. CdS nanostructured thin films have been shown exceptional third order nonlinear optical (TONLO) behavior near the sub band gap energy region. This review will be based on TONLO properties of CdS nanostructured thin films, which will focus on the tailoring of TONLO properties as a function of particle size, dopant and CdS polymer nanocomposite. Doping and size effect in CdS system is the important opportunity to develop it with excellent TONLO properties. This review paper will give an open area of research possibilities to search the efficient nonlinear optical CdS nanostructured thin films for advanced modern photonics applications and also will provide an idea to develop efficient materials with exceptional TONLO properties.
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•LALTA single crystals were grown by slow cooling technique.•Structural analysis was carried out.•High optical transparency was observed in the crystal.•Optical band gap was ...calculated and found to be 5.57eV.•Theoretical study was performed on LALTA crystal.
l-asparagine l-tartaric acid single crystals of size 14mm×12mm×5mm were grown. The morphology was recorded during its live growth process using inverted microscope. Structural confirmation of grown crystals was done by powder X-ray diffraction. The grown crystals are optically transparent. The Highest occupied molecular orbital and lowest unoccupied molecular orbital energy gap was obtained using the RHF/6-31G(d,p) and B3LYP/6-31G(d,p) level of theoretical calculations. The dipole moment calculated by RHF is 5.1716 D and by B3LYP is 2.8302 D. The calculated gas phase polarizability is 16.63791Å3.
Aluminum-doped zinc oxide (AZO) thin films were deposited by sol–gel spin coating technique onto the glass substrates using different solvents such as 2-methoxyethanol, methanol, ethanol and ...isopropanol. Prepared films were characterized by XRD, Raman spectrum, SEM, UV–visible spectrophotometer, photoluminescence (PL) and electrical studies. XRD studies showed that all the prepared films are hexagonal wurtzite structure with polycrystalline nature oriented along (002) direction. SEM images showed uniform particles of size around 60 nm distributed regularly on to the entire glass substrate. EDX analysis confirmed the composition of grown AZO film consisting of Al, Zn and O elements. The prepared films showed highest optical transmittance ~ 94% in the visible range and band gap 3.30 eV. PL spectra for all AZO films showed a strong UV emission peak at 387 nm. The AZO films prepared using isopropanol solvent showed high carrier concentration and low resistivity values as 1.72 × 10
20
cm
−3
and 2.90 × 10
−3
Ω cm, respectively, with high figure of merit (
ϕ
) value 8.42 × 10
−3
(Ω/sq)
−1
.
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 (
n
2
) and absorption coefficient (
β
) and third-order nonlinear susceptibility
(
χ
3
)
values were determined using
Z
-scan and observed in order of 10
–8
cm
2
/W, 10
–4
cm/W and 10
–3
esu, correspondingly. The high values of
χ
3
propose the films for nonlinear applications.
In this work, an Ag2O modified g-C3N4/TiO2 ternary heterogeneous photocatalyst was prepared through simple calcination and efficient hydrothermal synthesis way. The as-prepared composites were ...analyzed by powder XRD, FT-IR, HRSEM with EDX mapping, HRTEM, XPS, UV-Vis DRS and PL spectra respectively. The Ag2O modified g-C3N4/TiO2 photocatalyst displays a narrower bandgap and improved the RhB dye photo-degradation efficiency was reached at ~94.5% for 60 min under visible light exposure. Also, the reaction rate constant (k) of RhB dye and phenolic impurities degradation efficiencies for g-C3N4/TiO2-Ag2O PCs was 5.8 and 4.97 folds higher than that of pristine g-C3N4. Besides, the g-C3N4/TiO2-Ag2O composite PCs sustained superior photo-degradation performance after the five reusability tests, indicating excellent stability and durability. The excellent photocatalytic performance has been attributed to the synergistic heterostructured formation between Ag/Ag2O among g-C3N4/TiO2 composites, which facilitates the interfacial electron separation/transfer, and great visible-light utilization ability. For experimental results, a possible photo-degradation mechanism was also proposed.
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•Ag2O modified g-C3N4/TiO2 photocatalyst was prepared by hydrothermal synthesis way.•g-C3N4/TiO2-Ag2O displayed 5.8 times superior to g-C3N4 degradation efficiency.•g-C3N4/TiO2-Ag2O catalyst ensured superior degradation process after five recycling.•A possible photo-degradation mechanism was also proposed.•Ag2O SPR effect was deposited on the g-C3N4/TiO2 surface plays an electron bridge.
Nanostructured NiO thin films are fabricated with various concentrations of Fe through a simple spin-coating route and studied for its possible nonlinear optoelectronic applications. The grown films ...are of good crystallinity grown along (111) plane with single phase of NiO approved by X-ray analysis. The crystallite size values were calculated and noticed to be reduced from 36 to 8 nm with increasing Fe-doping content. Furthermore, FT-Raman spectroscopy also confirmed single phase. EDX approves the presence of Ni, O and Fe in final films and SEM elemental mapping shows homogeneous doping of Fe throughout the NiO films. AFM topographic study reveals the grain size and roughness varies with increase of Fe contents into NiO. The optical study reveals that the grown films are of high transparency which is about 70–85%. The estimation of various optical parameters was done, and direct energy gap found in 3.60 to 3.64 eV region for 0.0, 1, 2.5 and 5 wt% Fe:NiO films, correspondingly. The nonlinear properties were investigated and the values of
χ
1
,
χ
3
, and
n
2
were found to be improved from 0.16 to 0.54, 1.3 × 10
–13
to 1.25 × 10
–11
esu and 2.67 × 10
–12
to 1.70 × 10
–10
esu, respectively. The enhancement in linear and nonlinear parameters owing to Fe-doping content makes the fabricated films more useful in optoelectronics.
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