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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.

A novel luminescent multifunctional 3D Zn(ii)-pyridylimidazoquinazoline MOF was synthesised and used as a selective sensor for the detection of Al3+ and trinitrophenol and to fabricate a Schottky diode with improved photo-conductivity.

The optoelectronic properties of two cadmium based complexes have been examined both experimentally and theoretically. The energy associated with non-covalent interactions observed in the solid state of both complexes has been calculated.

Bovine Serum Albumin protein-based two fascinating functional self-healing Cu(II) metallohydrogel scaffolds (MD1 and MD2) have been studied for the development of metal-semiconductor junction based Schottky diode device. Multiple metal-semiconductor (MS) junction devices, offering the sandwich-like configuration of Indium tin oxide (ITO)/ metallogel/Aluminium (Al), have been made-up to investigate the electrical properties of the synthesized metallohydrogel materials. Optical characterizations including optical band gap measurement have been carried out using Tauc's equation for both the metallohydrogels. The current-voltage (I-V) characteristics of just made-up devices are studied under irradiation and non- irradiation conditions to explore the electrical features through investigating the charge transport phenomenon. The electrical conductivity gets estimated as 3.13 × 10

Herein, we have presented the crystal structure, supramolecular structure and band structure along with dielectric, electrical transport and optoelectronic properties of a [Mg(H2O)6]2+ templated 3D hydrogen bonded supramolecular framework (HSF) {[Co(2,5-Pdc)2,(H2O)2]2−·[Mg(H2O)6]2+·4(H2O)} (where 2,5-pdc = 2,5-pyridinedicarboxylate) synthesized by reflux method. The complex crystallizes in the P space group. The 3D network of the complex has been built up by hydrogen bonding interactions between 2D supramolecular sheets of the complex. The proton conductivity and activation energy of the complex are ∼10−4 S cm−1 at 40 °C and ∼0.3 eV, respectively, under vacuum. It exhibits anomalous dielectric behavior due to the gradual release of guest water molecules above 40 °C. The complex is a semiconductor with a band gap of 1.626 eV and is capable of absorbing electromagnetic radiation in the range of 355–730 nm. The ITO/complex/Al sandwiched device exhibits Schottky barrier diode (SBD)-like behaviour with a rectification ratio of 13 in the dark and 34 under visible light at 1 V. When exposed to visible light (AM 1.5G) the value of its conductivity enhances 1.35 times, compared to that in the dark. It has been shown that the complex is a semiconducting proton conducting photoresponsive HSF.

Terpyridinium salts of hydracids [PTPH3](Br)3·H2O (1), [PTPH3](Cl)3·2H2O (2) and oxoacid [PTPH3](ClO4)3·H2O (3) (PTP = 4′-(3-pyridyl)-4,2′:6′,4′′-terpyridine) were synthesized and characterized using single crystal X-ray diffraction analyses. The crystallographic analysis reveals that the π+⋯π, π+⋯π+, anion⋯π and anion⋯π+ interactions play a crucial role in the stabilization of the self-assembled structure, which in turn is responsible for enhancing the dimensionality of all the compounds. All the compounds confirm their usefulness as optoelectronic devices owing to the pronounced electrical conductivity and photosensitivity. Experimental and theoretical observations clarify an increase in the electrical conductivity on irradiation compared to dark conditions, especially in 3.

A functionally advanced Ni(II)-metallogel (Ni-D-TA) was prepared through the sonication of nickel(II) chloride hexahydrate and 4,4′-dipyridyl and triethyl amine in an N,N-dimethyl formamide solvent at room temperature under ambient conditions. The rheological investigation proves the mechanical stability of the functional Ni-D-TA metallogel. FESEM microstructural analysis unveils a rock-like morphology with a self-assembled architecture of the Ni-D-TA metallogel. The optical and electrical properties of the metallogel were thoroughly examined, and the results indicate the semiconducting nature of Ni-D-TA. Electrical conductivity and photosensitivity show its capability in optoelectronic device application. Also, it is seen from the experimental studies that light irradiation endows the metallogel with better device parameters and charge transport properties. The rectification ratio increases to two-fold under illumination. This type of metallogel with photosensing Schottky behaviour advances the area of optoelectronic devices.

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.

We have introduced an extremely low-molecular-weight organic gelator with a Cd(II) source to obtain a supramolecular Cd(II) metallohydrogel. Microstructural analysis of the gel has been performed. ...

The combination of two 8-aminoquinoline-based Schiff base ligands (L1 and L2) with SCN– and Ni(II) has led to the synthesis of two new one-dimensional thiocyanato-bridged coordination polymers: [Ni...

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 heteroporous metal–organic framework, [Cd2(2,2′-DSB)2(INH)2(H2O)2]n (1), is fabricated by the reaction of CdI2, 2-mercaptobenzoic acid (2-MBAH), and isoniazid (INH). The X-ray structure of the co...

An intriguing functional supramolecular Tb(III)-metallogel (Tb-OX) has been derived through the sonication of Terbium(III) chloride hexahydrate and oxalic acid dihydrate in N,N-dimethyl formamide (...

Here, glancing angle deposition is employed to synthesize the undoped GeO2 and Mg-doped (0.4 and 0.8 at. %) GeO2 nanowires (NWs) on a Si substrate. The microscopic images show the formation of the NW-like morphology of the grown materials. The gradual decrease in the average ratio of length to diameter depicts the worsening of the formation of NWs with the incorporation of Mg into the GeO2 host lattice. This also affects the crystallinity characteristics of the materials, which have been demonstrated from the selected area electron diffraction (SAED) pattern of the materials. The polycrystallinity nature of undoped GeO2 NWs changes to amorphous due to the introduction of Mg, which has been confirmed from both the obtained SAED and x-ray diffraction patterns of the samples. The presence of Mg was confirmed from the obtained broad bands at 473 and 437 cm−1 in the Fourier transmission spectrum of the doped samples. The increasing conductance with the temperature of Au/undoped GeO2 devices can be explained by the thermionic emission process, whereas the Mg-GeO2 device shows an overall decrease in conductance with increasing temperature. We have ascribed the origin of this abnormal conductance as the positive temperature coefficient of resistance, which is one of the first reports, due to the generation of random grain boundaries and enormous electron trapping at the Au/Mg-GeO2 NW junction. Furthermore, the undoped GeO2 NW device shows good temperature-dependent conductivity as well as stability compared to the doped one.

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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A newly designed multifunctional two-dimensional coordination polymer (2D CP) {[Cd(suc)(4-nvp)2]·2H2O}n, (1), (H2suc = succinic acid and 4-nvp = 4-(1-naphthylvinyl)pyridine) has been synthesized an...

A new copper(II) complex [CuL(NCS)] with a naphthalene based Schiff base, HL = (1-(2-(diethylamino)ethylimino)ethyl)naphthalene-2-ol, has been synthesized and characterized by elemental analysis as well as single-crystal X-ray diffraction studies. The complex crystallizes in the monoclinic space group P21/a. The complex shows C–H⋯π interactions to form a supramolecular chain structure. The electrical conductivity of the complex has been recorded under dark and irradiated conditions and the measured I–V characteristics of the complex under dark and light conditions indicate highly non-linear rectifying behavior, thus signifying a Schottky diode nature. The material is also photosensitive as the values of the electrical parameters are enhanced after exposure to illumination of incident radiation. The optical band gap of the complex in the solid state (2.92 eV) has been determined by experimental measurements and compared with the theoretical value obtained from DFT calculations (2.99 eV).

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.

Three Cd(II) based coordination polymers (CPs) (1–3) are designed using 3-aminoquinoline and 5-aminoquinoline based Schiff base ligands and thiocyanate and dicyanamide as bridging ligands. Pseudoha...

A functional supramolecular Mn(II)-metallogel (Mn@OX) has been synthesized through the direct mixing of manganese(II) acetate tetrahydrate and oxalic acid dihydrate, a low molecular weight gelator ...

A metal-organic compound [Cd(quin)2(4-nvp)2] [1; Hquin = quinoline-2-carboxylic acid and 4-nvp = 4-(1-naphthylvinyl)pyridine] undergoes topochemical [2 + 2] cycloaddition by sunlight irradiation to generate a one-dimensional coordination polymer. This reaction is thermally reversible, and switching between two crystalline forms can be monitored by conductivity measurements.

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.

Here, we have elucidated the structural, optical, magnetic and electrical properties of Cd0.8Fe0.2S which is considered as diluted magnetic semiconductor (DMS). Cd0.8Fe0.2S materials were synthesized using co-precipitation (compound 1) and hydrothermal (compound 2) method. The particle size and the polycrystalline phase of the synthesized materials are significantly influenced by the synthesis procedures. Presence of antiferromagnetic coupling confirms the magnetic behavior of materials. The current-voltage (I-V) characteristics exhibit lower barrier height for the device based on compound 2 (0.59 eV) than the other device (0.64 eV). Furthermore, the 19 times enhanced mobility and lesser density of states near the Fermi level for the Al/compound 2/ITO configured device is enlightened by the space charge conduction mechanism. But, the interface resistances of the devices cannot be distinguished by the I-V characteristics. Therefore, we have tackled the problem by simulating the Nyquist plots obtained from impedance spectroscopy. We have fitted the Nyquist plots with the appropriate equivalent circuit and explained the mechanism of charge transport through the Schottky interface. The higher dc conductivity and lower relaxation time of diode fabricated by compound 2 confirm the outcomes obtained from I-V characteristics. The effect of particle size on charge transport was also analyzed.

The porous materials are efficient storage and exchange systems of small molecules and ions. Some of the porous materials may be used as an efficient storage system of iodine. Herein, a honeycomb (...

An X-ray characterized tetranuclear nickel(II)/lead(II) complex has been synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction studies. Single crystal X-ray analysis confirms that the complex contains two [(NiO2)Pb] cores joined with two DMF molecules. The complex shows interesting electrical properties. The optical band gap energy of the synthesized ligand and the complex has been evaluated as 3.87 and 3.08 eV, respectively. The solid state UV measurement implies the semiconductor behavior of the complex. The complex based device has been determined experimentally to behave as a Schottky diode.

An intriguing rapid self-healing functional Mg(OH)2 metallogel was instantaneously developed through the direct mixing of monoethanolamine and magnesium nitrate hexahydrate as the source of magnesium ions in a water medium at room temperature under atmospheric pressure. The rheological properties of the Mg(OH)2 metallogel were scrutinized, and this revealed the mechanical toughness of the semi-solid metallogel material. The outcome of the rheological experiment showed the self-healing property of the metallogel. The self-healing feature was rapid and it occurred within a few minutes of the insertion of a crack into the metallogel or the association of two separate metallogel parts. The morphology of the metallogel was visualized through field emission scanning electron microscopy and EDX spectral investigations. The experimentally estimated optical band gap suggested the semiconducting nature of the material. The semiconducting nature of the metallogel was further verified from the electrical properties. Finally, a technologically challenging device-type application was also realized by the successful fabrication of a Schottky barrier diode, and different device parameters were investigated to verify the performance. The fabricated diode based on the Mg(II) metallogel showed a very high ON/OFF ratio of 85.52.

Herein, we report the synthesis, structural characterization and electrical conductivity of three new one-dimensional coordination polymers (1D CPs), [Cd(nip)(4-Clpy)(CH3OH)] (1), [Cd(nip)(4-Brpy)(CH3OH)] (2) and [Cd(nip)(4-Phpy)(H2O)]·DMF·3H2O (3) (H2nip = 5-nitroisophthalic acid, 4-Clpy = 4-chloropyridine, 4-Brpy = 4-bromopyridine, 4-Phpy = 4-phenylpyridine and DMF = N,N-dimethylformamide). The conductivity of the compounds was successfully tuned via the modification of the para-position of the 4-Xpy (X = Cl, Br and Ph) ligands. The electrical analysis indicated that compound 3 has the highest conductivity (22.25 × 10−4 S m−1) under illumination followed by 2 (19.38 × 10−4 S m−1) and 1 (12.68 × 10−4 S m−1). The optical characterization and density functional theory (DFT) computation also support the observed progression of conductivity in the materials. Here, the highest conductivity of compound 3 is attributed to the better π⋯π stacking interactions among the 4-Phpy and nip ligands, and the consequently increased charge transport between adjacent chains.

A heteroporous metal-organic framework, [Cd

We report here the synthesis of nanosized (50–55 nm) Fe-doped calcium copper titanate CaCu2.5Ti3.5FeO12 quadruple perovskite semiconductor by a two-step synthetic protocol involving citrate combustion for precursor synthesis followed by its calcination at different temperatures for the synthesis of the target materials. Materials were applied in thin film metal-semiconductor (MS) junction based Schottky Barrier Diodes (SBDs). The non-linear current-voltage characteristics indicate successful application of the materials in optoelectronic device. The device performance of the fabricated SBDs are analyzed by employing the thermionic emission (TE) theory and the space charge limited current (SCLC) theory followed by a schematic band structure.

In this report, we have synthesized Bornite (Cu5FeS4) material by hydrothermal synthesis technique. The interface characteristics of Al/Cu5FeS4/FTO Schottky barrier diode (SBD) are investigated by using ac impedance spectroscopy (IS) analysis (under dark condition) and dc current-voltage (I–V) measurements (under dark and light both condition). IS is a powerful tool to identify the interface regions of SBDs. Ac impedance spectra of Al/Cu5FeS4 SBD are recorded in the frequency range 40 Hz-20 MHz during dc bias scanning from -0.6 V to 0.6 V under dark condition. The diode parameter including ideality factor and barrier height is calculated from the conventional I–V measurement based on thermionic emission (TE) theory. Space charge limited current (SCLC) theory has been employed to further exemplify the improved performance of Cu5FeS4 based SBD, which points out that the carrier mobility is enhanced ∼2-fold after irradiation of light.

We present a two-step facile method to prepare Ni2O3 coral–like and flower–like nanostructures first time followed by structural, optical characterizations by XRD, FESEM, HRTEM, Raman, luminescence spectroscopy etc. We also report rectifying I–V characteristics of Ni2O3 nanostructures/Al based metal–semiconductor junction with ultralow turn-on voltages (0.36 V), potential barrier (0.33 eV), very ideal thermionic current (η = 1.11). Photo-responsive character illustrates that the junction devices could be a promising material for light sensing application. Parameters like series resistance (111.4 Ω), electron mobility (16.73 × 10−10 m2V1s−1), diffusion length (5.13 × 10−7 m), density of states (3.09 × 1040 eVm−3) etc. have been evaluated and it is discussed that the defect (Ni3+ vacancy) induced electron–phonon interaction within the active semiconducting layer plays the crucial role to determine these parameters. Most importantly, it has been identified that the charge-transport across the junction follows non-adiabatic mechanism. Our results suggest a new insight into current transport mechanism that may be generalized to understand microstructural, defect dependence MS junctions.

In this work, we have prepared copper (II) oxide (CuO) nanoparticles (NPs) via reflux (CuO (R)) and hydrothermal (CuO (H)) methods. The electrical parameters like rectification ratio, ideality factor and barrier height were compared between two synthesized CuO NPs after fabricating Al/CuO/ITO schottky barrier diode (SBD). Under dark, rectification ratio increased by 37% for CuO (H) than CuO (R). In a similar manner, photoresponse also significantly improved by a huge 93%. Impedance Spectroscopy measurements establish that CuO (H) shows better charge transport and lower carrier recombination compared to CuO (R). The enhanced device performance of the hydrothermally synthesized CuO based schottky diode can be attributed to the reduction in lattice defect density and its good thin film properties.