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Adipic acid, used as a low molecular weight gelator to fabricate a novel supramolecular metallogel of Zn(ii)-ions in DMF medium, gives an excellent microelectronic device of a Schottky barrier diode at room temperature.

This report presents an experimental study of electric and dielectric properties of hydrothermally synthesised molybdenum disulphide (MoS2) thin films using complex impedance spectroscopy (CIS). The measurements were taken in the bias voltage range 0 V–0.4 V and frequency 40 Hz–10 MHz. The CIS analysis depicts that both grain (bulk) as well as grain boundary effect has a significant role in the conduction mechanism of the compound. The frequency-dependent relaxation peak was observed in the impedance loss spectra with the upward rise in bias voltage. Also, we found that both real ( $${\varepsilon }{^{\prime}}$$ ) and imaginary part ( $${\varepsilon }^{{^{\prime}}{^{\prime}}}$$ ) of complex dielectric permittivity, both parts of electrical modulus (M′ and M′′) and AC conductivity of the MoS2 thin films are highly dependent on frequency. Existence of a single relaxation peak in electrical modulus plot further confirms the bulk effect in conduction. The varying ac conductivity plot with forward dc bias voltage endorses the occurrence of the hopping mechanism in the system, being well described by jump relaxation model (JRM). In short; this detailed study based on CIS shows the dielectric relaxation behaviour of MoS2 thin film and reflects the hopping induced conduction mechanism.

Here, we analyze inhomogeneities in the barrier height (BH) of Al/Cu5FeS4 Schottky device from the electrical ( ${I}$ – ${V}$ ) measurements with a temperature range between 303 and 408 K. The temperature-dependent performance of our fabricated device is analyzed by using the thermionic emission (TE) theory. Some important diode parameters like BH ( $\Phi _{\text {bo}}$ ), ideality factor ( $\eta $ ), and series resistance ( ${R}_{S}$ ) are evaluated from the forward current–voltage characteristic curves. The calculated $\eta $ and ${R}_{S}$ of the Schottky barrier diode (SBD) decrease, whereas the $\Phi _{\text {bo}}$ of the device increases with the increase in temperature. The value of Richardson constant (A*) for our material is obtained as $1.94\times $ 10−4 A cm−2 K−2 in the temperature range 303–408 K, which is found as much lesser than the theoretical value of 29.90 A cm−2 K−2. The discrepancy of A* from the theoretical value has been well explained by TE theory with the assumption of Gaussian distribution (GD) of BHs due to the existence of BH inhomogeneities at metal semiconductor (MS) junction. The obtained values of the mean BH $\overline {\Phi _{\text {bo}}}$ and the standard deviation $\sigma _{s}$ are 1.026 eV and 173 mV in the corresponding temperature range. The mean BH (1.199 eV) and Richardson constant (29.73 Acm−2K−2) are determined from the modified Richardson plot depending on the inhomogeneity of BHs. Apparent BH consists of mean BH ( $\overline {\Phi _{\text {bo}}}$ ) and standard deviation ( $\sigma _{\text {s}}$ ). The $\sigma _{\text {s}}$ contributes significantly to the modification of Richardson constant and mean BH. The calculated value of the modified Richardson constant is in close agreement with the theoretical value. From ${C}$ – ${V}$ measurements built-in voltage and effective BH of this structure were calculated as a function of frequency.

A fascinating way to originate a mechanically stable metallogel of ferric ions with metal-coordinating organic ligand triethylenetetramine through direct mixing of their water solutions in a stoichiometric ratio is achieved under ambient conditions. The rheological study established the mechanical property of the Fe(III) metallogel. A cashew-shaped microstructure of the metallogel was observed by FESEM analysis. The electrical property of the Fe(III) metallogel was also carefully scrutinized. The semiconducting features like the Schottky barrier diode property of the Fe(III) metallogel were explored. The catalytic role of the Fe(III) metallogel was also critically explored. The Fe(III) metallogel shows an excellent catalytic property toward the synthesis of aryl thioethers via a C–S coupling reaction under mild reaction conditions without the use of any organic solvent.

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Facile synthesis of Al-doped CaCu3Ti4O12 quadruple perovskite has been reported and it is projected to be a promising candidate for Schottky barrier diode application and a methanol steam reforming catalyst for hydrogen generation.

Described in this work is the synthesis of a novel dicyano-substituted N-2-aminoethyl-4-(3-pyridinyl)-2-pyridone organic compound (1) that is characterized by several spectroscopic methods. Compound (1) was utilized for the preparation of its perchlorate (2), chloride (3), and bromide (4) salts. Single-crystal X-ray structures of these three salts were determined, and noncovalent weak interactions involving the aromatic rings, anions, and water molecules in (2-4) were investigated in detail. Solid-state UV-vis spectrum of the reported compounds (1-4) was utilized to calculate their optical band gaps, which clearly indicated that they belong to the semiconductor family. Under illumination condition, the magnitudes of electrical properties of (1) and its salts (2-4) improve remarkably although the improvement differs from salt to salt and the result was analyzed theoretically. Salt (2) was tested for its DNA binding ability.

A new mixed-ligand divalent one-dimensional coordination polymer (1D CP) [Zn(adc)(4-nvp)2(H2O)2]n, (1) [H2adc = acetylenedicarboxylic acid and 4-nvp = 4-(1-naphthylvinyl)pyridine] has been synthesized and well characterized by elemental analysis, infrared spectrum, single-crystal X-ray crystallography, powder X-ray diffraction pattern, and thermogravimetric analysis. The compound 1 constructs a 3D supramolecular network by the combination of hydrogen bonding, C–H···π, and π···π interactions. Interestingly, the material shows Schottky behavior which is exclusively analyzed with the help of thermionic emission and space charge-limited current theory. In addition, the Schottky barrier diode parameters for compound 1 demonstrate better device performance after light soaking. Hence, the compound has applicability in the fabrication of optoelectronic devices.

Two novel Cu(II)-based metal-organic frameworks [C40H34Cu2N6O18 (1) and C20H18CuN2O10 (2)] have been synthesized using 2-aminopyrimidine or pyrazine ligands and phthalate ion and characterized spectroscopically and by X-ray single-crystal diffraction. Both 1 and 2 show electrical conductivity and photosensitivity, evidencing their potentiality in optoelectronic device applications. Experimental and theoretical investigations revealed that the electrical conductivity under irradiation of visible light increases compared to that under dark condition (photosensitive Schottky barrier diode behavior), especially in complex 2. Both 1 and 2 have been successfully applied in technologically challenging thin-film active devices.

In this report, bias voltage-dependent dielectric and electron transport properties of ZnS nanoparticles were discussed. ZnS nanoparticles were synthesized by introducing a modified hydrothermal process. The powder XRD pattern indicates the phase purity, and field emission scanning electron microscope image demonstrates the morphology of the synthesized sample. The optical band gap energy (Eg = 4.2 eV) from UV measurement explores semiconductor behavior of the synthesized material. The electrical properties were performed at room temperature using complex impedance spectroscopy (CIS) technique as a function of frequency (40 Hz-10 MHz) under different forward dc bias voltages (0-1 V). The CIS analysis demonstrates the contribution of bulk resistance in conduction mechanism and its dependency on forward dc bias voltages. The imaginary part of the impedance versus frequency curve exhibits the existence of relaxation peak which shifts with increasing dc forward bias voltages. The dc bias voltage-dependent ac and dc conductivity of the synthesized ZnS was studied on thin film structure. A possible hopping mechanism for electrical transport processes in the system was investigated. Finally, it is worth to mention that this analysis of bias voltage-dependent dielectric and transport properties of as-synthesized ZnS showed excellent properties for emerging energy applications.

Here we have approached the plausible use of CuFeS2 nanocomposite as an acceptor in organic–inorganic hybrid solar cell. To produce CuFeS2 nanocomposite, hydrothermal strategy was employed. The room-temperature XRD pattern approves the synthesized material as CuFeS2 with no phase impurity (JCPDS Card no: 37-0471). The elemental composition of the material was analyzed from the TEM-EDX data. The obtained selected area electron diffraction (SAED) planes harmonized with the XRD pattern of the synthesized product. Optical band gap (4.14 eV) of the composite from UV–Vis analysis depicts that the synthesized material is belonging to wide band gap semiconductor family. The HOMO (− 6.97 eV) and LUMO (− 2.93 eV) positions from electrochemical study reveal that there is a possibility of electron transfer from MEH-PPV to CuFeS2. The optical absorption and photoluminescence spectra of MEH-PPV:CuFeS2 (donor:acceptor) composite were recorded sequentially by varying weight ratios. The monotonic blue shifting of the absorption peak position indicated the interaction between donor and acceptor materials. The possibility of electron transfer from donor (MEH-PPV) to acceptor (CuFeS2) was approved with photoluminescence analysis. Subsequently, we have fabricated a hybrid solar cell by incorporating CuFeS2 nanocomposite with MEH-PPV in open atmosphere and obtained 0.3% power conversion efficiency.

The current–voltage (I–V) measurements on Al/ZnS Schottky barrier diodes in the temperature range 303 –423 K by the step of 15 K were carried out. The forward I–V characteristics were analyzed on the basis of the thermionic emission theory. The temperature dependence I-V parameters such as ideality factor (n) and barrier height (ϕ b0 ) have been explained on the basis of inhomogeneity. An abnormal increase of apparent barrier height and decrease of ideality factor with increasing temperature have been explained due to the barrier height inhomogeneities on the basis of the thermionic emission theory with Gaussian distribution. Experimental results reveal the existence of a single Gaussian distribution with apparent barrier height value ( ϕ b 0 ‾ ) of 1.091 eV and standard deviations (σ s ) of 0.18 V. Richardson constant (A*) was obtained as 8.49 x 10 -2 A.m -2 K -2 from the ln(I 0 /T 2 ) vs. q/kT plot, which is far from the calculated value of 5.6 x 10 5 A.m -2 K -2 . The modified Richardson plotof ln(I 0 /T 2 ) – (q 2 σ s 2 /2k 2 T 2 ) gives ϕ b 0 ‾ and A* values as 1.093 eV and 6.07 x 10 5 A.m -2 K -2 , without using the temperature coefficient of the barrier height. This obtained value of A* is extremely close to the previously calculated value. So, the temperature dependence of the forward bias I - V characteristics of the Schottky device can be successfully explained on the basis of the thermionic emission mechanism with a single Gaussian distribution of the barrier heights.

In this literature, we have investigated the magnetic properties and Schottky device-based charge transport properties of hydrothermally derived Mn0.04Cu0.05Zn0.91O nanorod. The doping of 3-D transitional metals, Mn and Cu, within ZnO makes it potentially applicable in spin-based electronics, whereas its temperature-dependent conductivity (of the order of 10−3 in C.G.S.) makes it suitable for semiconductor-based devices. The observation of intrinsic ferromagnetism of the synthesized composite and its variation of magnetization with magnetic field and temperature exhibited the suitability of spin-based electronic application. To check the applicability in optoelectronic devices, metal–semiconductor (Al/Mn0.04Cu0.05Zn0.91O) junction was fabricated and analyzed. The current–voltage characteristic represented the rectifying behavior of the junction with on/off current ratio 4.3 at ±1 V in dark and potential barrier height 0.61 eV. The significant change in rectification due to the influence of incident radiation makes this material suitable for photosensing electronic device application.

Transparent-conducting InZnO:Ga (IZO:Ga) thin films have been developed on glass substrate at room temperature (300K) by nonreactive RF-Magnetron sputtering using sintered ceramic disc of InZnO:Ga target (In-10 wt%, Ga -3wt% and Zn -87wt%). The novelty of very thin IZO:Ga films are low resistivity (1.5×10−3 Ω.cm) and low sheet resistance (20 Ω/□) with average optical transmittance 86%, large Haze factor (>70%) and high figure of merit value (1.1×1018) respectively. RF-sputtered IZO:Ga films shows amorphous nature, smooth and crack-free surface morphology and topography with predominant metallic phase. Heat treated samples becomes crystalline, topography becomes more aligned (U-type) and surface roughness increases.

In this work, we have incorporated strontium (Sr) into cadmium sulphide (CdS) complex to explore its effect on optical and electrical properties. In this regard Sr composited CdS and a bared CdS were prepared by hydrothermal technique. X-ray diffraction pattern of the materials were analyzed to obtain their crystalline structure, size and internal lattice strain. The compositional details were obtained from SEM-EDAX study. The optical properties of the films of synthesized materials were analyzed. The dependency of refractive index on incident photon energy was studied in detail for each material. The dispersion energy related parameters, dielectric relaxation constant and optical conductivity followed by dispersion of the refractive index were determined and discussed by employing the single electronic oscillator model. From wavelength dependent refractive index data, the plasma frequency, ratio of free charge carrier concentration to effective mass, lattice dielectric constant and high frequency dielectric constant were calculated to determine the discrepancy of the compounds. The third order optical susceptibility was analyzed to check their potential ability of performance in optical limiter and optical switching device application. The electrical characterization was performed by measuring the current–voltage characteristics of structure ITO/CdS:Sr/Al and ITO/CdS/Al. The rectifying I–V showed improved On/Off ratio under dark (25.03 and 19.98) and light (35.51 and 25.09) for ITO/CdS:Sr/Al compared to ITO/CdS/Al. The dark and photoconductivity of the film were also determined for both the films. The time dependent current response was analyzed at constant bias voltage ±1 V.

Schiff-base compounds have rarely been employed in optoelectronics. Herein, we report the optical and electrical properties of a Schiff-base compound, 1,4-bis-(quinolin-6-yl iminomethyl)benzene (BQB), in detail. The electrical properties of BQB have been studied with a thin film made of it. The results of electrical conductivity and measurement of optical band gap of BQB encouraged us to examine its potential application in metal (Al)-semiconductor Schottky diode. I–V measurement of ITO/BQB/Al configuration illustrated its Schottky behavior with a moderate rectification ratio at applied bias potential of ±1.0 V. The characteristic diode parameters were obtained. The device showed a good ideality factor of 1.2 and low barrier height of 0.44 eV. Charge transport properties through the metal semiconductor junction, which is critical for device performance, were analyzed by space charge-limited current theory. In this regard, mobility–lifetime product, carrier density, density of states at Fermi level and diffusion length was estimated. The results show that this new Schiff-base compound has the potential for successful application in thin film semiconductor device.

Here, we have discussed the electron transport phenomena through the interface formed by aluminium and hydrothermally synthesized Zinc-Cadmium-Sulphide (ZnCdS) nanocomposite. In this background, the structural, optical, and electrical characterization of the synthesized material were studied. The estimated optical band gap energy (=3.14 eV) and the room temperature conductivity (1.6 × 10−6 S cm−1) of the synthesized nanomaterial motivated us to explore the metal/inorganic-semiconductor interface. The carrier transport mechanism under dark and light-illuminated conditions was analyzed by the thermionic emission theory of the metal–semiconductor junction. Significant changes in rectification ratio, barrier potential, and the ideality factor were observed under light irradiance. The effect of incident radiation on mobility-lifetime (μτ) product and the diffusion length (L D) was demonstrated for the device.

Three salts [perchlorate (2), chloride (3) and tetrafluoroborate (4)] were synthesized from a 1-(2-aminoethyl)-6-hydroxy-2-oxo-1,2-dihydro-[4,4-bipyridine]-3,5-dicarbonitrile compound (1) and characterized by spectroscopic and single crystal X-ray diffraction methods. Various noncovalent interactions (e.g., anion(+), , lp) are explored in the solid state crystal structure of the salts. Optical band gaps of all the four compounds were determined from their solid-state UV-vis spectrum. Electrical properties like electrical conductivity, photosensitivity, etc. were calculated and the results revealed that they have potential to act as optoelectronic devices. The values of the electrical parameters increase several times when they are exposed to visible light rather than in dark conditions. The light sensing properties of the salts (2-4) are enhanced compared to that of the mother organic compound 1 but the magnitude of this enhancement is not same for the three salts. This observation has been rationalized by theoretical considerations. Moreover, the DNA binding ability of one of the representative salts (compound 2) was examined to check the biological importance of the synthesized salts., TM thankfully acknowledges the UGC, New Delhi for a senior research fellowship. We thank the MINECO/AEI from Spain for financial support (project number CTQ2017-85821-R, FEDER funds). We are grateful to the CTI (UIB) for free allocation of computer time.

In this report the synthesis of novel zinc oxide (ZnO) with a lower defect density and its effect on the Al/ZnO Schottky junction has been demonstrated. The defect density was estimated by positron annihilation lifetime measurement which ensures the material's superiority (i.e. free from point defects or any type of vacancies) over the earlier reported results. The thin film device of synthesized ZnO was fabricated on an ITO coated glass substrate. As the front contact was made by aluminium, the characteristic I–V produced rectifying Schottky behavior. The underlying charge transport mechanism through a metal–semiconductor (i.e. Al/ZnO) junction was analyzed on the basis of thermoionic emission theory to find out the quality of the fabricated device. In this regard we have studied the charge transport mechanism by measuring the density of states (DOS) at the Fermi level, mobility-lifetime product and diffusion length.

A novel synthesis of CuFeS2 nanoparticles has been demonstrated here. This is the first time we have thoroughly investigated the frequency dependent dielectric behavior of iron-chalcopyrite (CuFeS2) pellets (with σd.c. = 47.27 × 10−9 S cm−1). The room temperature a.c. conductivity of the material has also been investigated in the frequency range 200 Hz–2 MHz. Frequency dependent impedance analysis of the material indicates the charging and discharging behavior of the capacitor. Throughout this report we have analyzed the frequency dependent complex impedance, electric modulus and the loss tangent of the CuFeS2 pallet as series and parallel combinations of capacitors and resistors.

The presence of a Schottky barrier (SB) at a metal–semiconductor (MS) interface is of paramount importance to numerous application fields. In this report, we demonstrate the performance comparison of Schottky diodes fabricated with TiO2 and rGO–TiO2 nanocomposites, in contact with aluminium. From forward I–V characteristics, important diode parameters i.e. rectification ratio, ideality factor, series resistance and barrier height were obtained. A photoresponse comparison of the diodes has also been performed. It was found that the rGO–TiO2 based junction showed improved performance. The rectification ratio increased by ∼94% and the barrier height was lowered by ∼10%, under dark conditions. For better realization of the junction, here we provide insight into the carrier transport properties with the help of space charge limited current (SCLC) theory. After introducing graphene, the carrier mobility and carrier concentration increased by 64% and 21% respectively, while the diffusion length is found to be improved by 13.4%. These results illustrate that rGO incorporation has led to a much improved carrier transport and electron hole separation. Due to greater light absorption, the improvement in diode parameters and transport properties were even better when the device was subjected to irradiation.

In this study, we have synthesized semiconducting ZnO nanoparticles (NP) of different morphology in solvothermal route, by using different capping reagents and applied it as an acceptor in poly(2-methoxy-5(2-ethylhexyloxy)-phenylene-vinylene (MEHPPV):ZnO NP based hybrid photovoltaic devices. Material properties of ZnO NP of different morphology and the compositions were studied with the help of X-ray diffraction, scanning electron microscopy, fourier transform infrared and thermo gravimetric analysis. The direct band gap energies of flower, sphere and rod-like ZnO NP were calculated as 3.68, 3.15 and 3.25 eV by using Tauc’s plot with the help of UV–Vis absorption. We have studied different material properties of MEHPPV:ZnO composite to check their applicability as an active layer of hybrid solar cell. Photo-luminescence (PL) spectra of the composite materials were recorded to check PL energy quenching which is quite noticeable in case of sphere-like nanoparticle. Finally the hybrid solar cell of the structure ITO/PEDOT:PSS/MEHPPV:ZnO/Al has been fabricated and studied. From the current density (J)–voltage (V) characteristic, we have found that the solar cell fabricated with ZnO sphere-like structure gives better result.