Water Tetramer Confinement and Photosensitive Schottky Behavior of a 2D Coordination Polymer

Electrical and Photodetector Characteristics of Schottky Structures Interlaid with P(EHA) and P(EHA-co-AA) Functional Polymers by the iCVD Method

In this study, poly(2-ethylhexyl acrylate) (PEHA) homopolymer and its copolymer combined with acrylic acid P(EHA-co-AA) were employed as interfaces in two separate Schottky structures. First, both interfaces were grown by initiated chemical vapor deposition (iCVD), which provides much better deposition control and homogeneous coating compared to solution-phase methods. In addition to this advantageous method, the effects of two different polymers, one of which is better able to adhere to the crystal surface on which it is formed than the other, on the optoelectronic properties have been studied. Then, their current-voltage (I-V) and capacitance/conductance-voltage (C/(G/ω)-V) characteristics were investigated both in the dark and under illumination. The basic electrical parameters and the illumination-induced profile of the surface state (Nss) were probed by I-V and C-V measurements for two samples. A decrease in the barrier height (BH) and, consequently, a significant increase in the photocurrent were observed under illumination. Striking changes in series resistance (Rs) values are also highlighted. The photocapacitance and conductance characteristics indicated that the structures could be considered not only as photodiodes but also as photocapacitors. Moreover, the voltage-dependent changes of some photodetector parameters, such as responsivity (R), sensitivity (S), and specific detectivity (D*), along with the transient photocurrent characteristics, are discussed for both structures. Therefore, we can say that the strong changes in these parameters, which figure the merit of photodiode and photodetector applications, depending on the voltage and under illumination, prove that it is a study carried out in accordance with the purpose and so they can be used in electronic and optoelectronic applications.

Coordination polymers: a promising candidate for photo-responsive electronic device application

The design and synthesis of electrically conductive coordination polymers (CPs) are of special interest due to their applications in the fabrication of many environmentally benign emerging technologies, such as molecular wires, photovoltaic cells, light emitting diodes (LEDs), field effect transistors (FETs) and Schottky barrier diodes (SBDs). Owing to their structural flexibility, easy functionality and adjustable energy levels, CPs are promising candidates for providing a better pathway for superior charge transport. Again, the utilization of visible light as an external stimulus to control and manoeuvre the electrical properties of the CPs is exceptionally motivating for the development of many optoelectronic devices, such as photodetectors, photo-switches, photodiodes and chemiresistive sensors. The applications of such materials in devices will solve questions regarding the energy crisis and environmental concerns. This study provides an overview of the recent advances in the development of photo-responsive CPs and the possibility of their application in developing optoelectronic devices. In this regard, a thorough literature survey was performed and the studies related to the fabrication of photosensitive conducting CPs for applications in optoelectronic devices are listed.

In Situ Oxidation of Pyridyl-Dihydrobenzoimidazoquinazoline and the Synthesis of a Highly Luminescent Cd(II) Coordination Polymer: A Promising Candidate for Mutagenic Nitroaromatic Detection and Device Fabrication

Pyridyl-substituted imidazoquinoline, a potent fluorescent framework, is advantageous to architect multifunctional coordination networks for sensing and fabricating emergent electrical conductors. In this work, a Cd(II)-based one-dimensional (1D) coordination polymer (1D CP), [Cd(glu)2(pbiq)2(H2O)]n (1), [H2glu = glutaric acid and pbiq = 4-(6-(pyridin-4-yl)benzo[4,5]imidazo[1,2-c]quinazoline)], has been structurally confirmed by single-crystal X-ray crystallography. The H-bonding and π···π interactions built a three-dimensional (3D) supramolecular structure that strongly emits at 416 nm in acetonitrile suspension. Potentially intrusive nitroaromatics (NAs) and trinitrophenol (TNP) selectively quench the strong emission of 1, and the highest quenching is noted in the case of TNP. A detection limit (limit of detection (LOD)) of 1.51 × 10-7 M for TNP is determined. The band gap (3.31 eV) of 1 recognizes semiconducting behavior, and an electronic device is fabricated. The correlation of current vs voltage (I-V plot) reveals a substantial non-ohmic electrical conductivity of 1 (Λ: 1.10 × 10-5 S m-1) along with a low energy barrier (ΦB: 0.69), and the series resistance (Rs) becomes 6.21 kΩ.

Synthesis and crystal structure of catena-poly[[hexa-aqua{μ3-2-[bis-(carboxyl-atometh-yl)amino]-terephthalato}dicobalt(II)] penta-hydrate] containing water tapes and penta-mers

The title coordination polymer, {[Co2(C12H7NO8)(H2O)6]·5H2O} n , was crystallized at room temperature from an aqueous solution of 2-aminodi-acetic terephthalic acid (H4adtp) and cobalt(II) nitrate. The asymmetric unit consists of one adtp4- ligand, one and two half CoII ions, six water ligands coordinated to CoII ions and five uncoordinated water mol-ecules. Two of the cobalt cations lie on centres of inversion and are coordinated in octa-hedral O2(OH2)4 environments, whereas the other adopts a slightly distorted octa-hedral NO3(OH2)2 environment. The crystal structure contains parallel stacked, one-dimensional zigzag chains, {[Co2(C12H7NO8)(H2O)6]} n , which assemble into a three-dimensional supra-molecular architecture via networks of hydrogen bonds involving the coordinated and free water mol-ecules. One-dimensional 'water tapes' are formed, containing alternating six-membered and twelve-membered rings of water mol-ecules, together with water penta-mers, in which a central uncoordinated water mol-ecule is hydrogen bonded to two coordinated and two free water mol-ecules in a tetra-hedral arrangement.

Semiconducting properties of pyridyl appended linear dicarboxylate based coordination polymers: theoretical prediction via DFT study

Coordination polymers (CPs) in recent times have emerged as active constituents in many semiconductor devices like light emitting diodes (LED), field effect transistors (FET), photovoltaic devices and Schottky barrier diodes. An intelligent choice of linkers, careful selection of metal ions and post synthetic modification (PSM) can provide a better pathway for charge transportation. However, a proper understanding of the charge transport mechanism in CPs is still inadequate due to the lack of considerable experimental and theoretical work. In this paper, we address the theoretical elucidation of semiconducting properties and a probable pathway for charge transportation in three of our previously published CPs using density functional theory (DFT). These results help us to recognize the orbitals that have major contributions in the formation of the valence band and also provide the most likely pathway for optimum electronic communication. In this regard, the role of hydrogen bonding and unpaired electrons of metal d-orbitals is also established.

Nickel(ii) di-aqua complex containing a water cluster: synthesis, X-ray structure and catecholase activity

A trans-diaquanickel(ii) complex with a tetradentate aryloxyacetic acid ligand that forms a six membered water cluster in crystals and exhibits catecholase activity with a good turnover number is reported.

Electrically conductive 1D coordination polymers: design strategies and controlling factors

Due to the easy functionality and structural diversity of coordination polymers (CPs) coupled with superior thermal stability, many researchers have been prompted to explore the opportunity of introducing these hybrid materials as active components in various electronic devices, such as light emitting diodes (LED), solar cells, field effect transistors (FET), and Schottky barrier diodes (SBD). Therefore, the judicious selection of the structural components of CPs is directly related to their structure-property relationship and applications. One-dimensional (1D) CPs have recently emerged as excellent electrical conductors and are gaining enormous attention owing to their simple chain-like coordination arrays. In this article, we review the rational design strategies for synthesising 1D CPs and also point out the structural factors that affect the charge transport properties as well as the electrical conductivity of these materials.

Stabilization of cyclic water tetramers and dimers in the crystal host of 2D coordination networks: electrical conductivity and dielectric studies

Construction of Zn(ii)-based 2D coordination polymers for selective recognition of water tetramers and dimers in crystal hosts and their exploitation in electrical studies.

Synthesis of a Zn(ii)-based 1D zigzag coordination polymer for the fabrication of optoelectronic devices with remarkably high photosensitivity

This study presents the fabrication of a novel Zn(ii)-based 1D zigzag coordination polymer, which shows remarkably high photosensitivity and has the potential to be used in photoswitching devices and solar cells.

An acetylenedicarboxylato-bridged Mn(ii)-based 1D coordination polymer: electrochemical CO2 reduction and magnetic properties

A Mn(ii)-based 1D coordination polymer, [Mn(adc)(4-phpy)₂(H₂O)₂]_n, (H₂adc = acetylenedicarboxylic acid and 4-phpy = 4-phenylpyridine) showed dual properties: electrochemical CO₂ reduction and anti-ferromagnetism.

Supramolecular Assembly of a Zn(II)-Based 1D Coordination Polymer through Hydrogen Bonding and π···π Interactions: Crystal Structure and Device Applications

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.