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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.

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.

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).

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.

Two new one-dimensional coordination polymers (1D CPs) {[Zn(adc)(4-spy)2(H2O)2]}n (1), and {[Cd(adc)(4-spy)2(H2O)2]}n (2) (H2adc = acetylenedicarboxylic acid and 4-spy = 4-styrylpyridine), have been synthesized and well characterized. Single crystal X-ray diffraction data exhibit that compounds 1 and 2 are isostructural and undergo hydrogen bonding and C–H⋯π interactions to construct 3D supramolecular architectures. Electrical characterization reveals that both compounds show substantive electrical conductivity and exhibit Schottky diode nature. However, compound 2 has a higher mobility and higher conductivity compared to 1. The estimated values of effective carrier mobility, transit time, carrier concentration and diffusion length demonstrate that the charge transport properties have been improved for 2. Therefore, compound 2 has better performance in the fabrication of electronic devices.

In this study, an acetylenedicarboxylate based binuclear Cu(II) compound [Cu2(adc)(4-pic)6(H2O)4][ClO4]2 (1) (H2adc = acetylenedicarboxylic acid and 4-pic = 4-picolene) has been synthesized and well characterized using elemental analysis, infrared (IR) spectra, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) patterns and single crystal X-ray diffraction (SCXRD) techniques. The binuclear compound undergoes hydrogen bonding interactions to form a 1D hydrogen bonded aggregate, which further undergoes extensive edge-to-face C–H⋯π interactions to form a 3D supramolecular motif. The current conductivity of compound 1 was recorded under dark and illuminated conditions. Interestingly, the measured I–V characteristics of the synthesized material in the dark and under the illumination of incident light exhibit a highly non-linear rectifying behavior signifying a Schottky diode nature. Furthermore, the enhancement of values of the electrical parameters after exposure to illumination of incident radiation indicates the light sensing behaviour of the material. Therefore, the material can be used as a promising candidate in photosensitive electronic devices.

Azo based organic semiconductor molecules are mostly used as write once, read-many-times (WORM) memory systems. Therefore, a large scope still remains in the fabrication of photoconducting azo compounds, which can be used under acute conditions for advanced applications. In this context we have designed a very simple, small azo based organic molecule, viz. [1,4-phenylenebis(azanylylidene)bis(methanylylidene)bis(2-methoxy-4-(phenyldiazenyl)phenol)] (compound 1). The device fabricated using compound 1 showed Schottky barrier behavior. The value of the rectification ratio is 6.22 and 18.27 under dark and photoirradiated conditions, respectively. Thermally stable and low cost compound 1 can be used in the area of optoelectronic devices probably being the first azo-organic material showing such properties. Experimentally measured optical conductivity is again correlated theoretically using DFT computation. It has been observed that the change in the dihedral angle produces a decrease in the energy for the allowed electronic transition.