Deposition of polyaniline via molecular self-assembly on TiO2 and its uses as a sensitiser in solid-state solar cells

Polyaniline nanofibers: broadening applications for conducting polymers

Polyaniline is a conducting polymer with incredible promise, but it has had limited use due to poor reaction control and processability associated with conventional morphologies. Polyaniline nanofibers, on the other hand, have demonstrated, through manufacturing techniques discovered during the past decade, increased processability, higher surface area, and improved consistency and stability in aqueous dispersions, which are finally allowing for expanded commercial development of this promising polymer. This review explores some intriguing applications of polyaniline nanofibers, as well as the advantages and remaining challenges in developing better products using polyaniline in this new morphology.

Visible light-induced photocatalytic degradation of Reactive Blue-19 over highly efficient polyaniline-TiO2 nanocomposite: a comparative study with solar and UV photocatalysis

Polyaniline-TiO₂ (PANI-TiO₂) nanocomposite was prepared by in situ polymerisation method. X-ray diffractogram (XRD) showed the formation of PANI-TiO₂ nanocomposite with the average crystallite size of 46 nm containing anatase TiO₂. The PANI-TiO₂ nanocomposite consisted of short-chained fibrous structure of PANI with spherical TiO₂ nanoparticles dispersed at the tips and edge of the fibres. The average hydrodynamic diameter of the nanocomposite was 99.5 nm. The band gap energy was 2.1 eV which showed its ability to absorb light in the visible range. The nanocomposite exhibited better visible light-mediated photocatalytic activity than TiO₂ (Degussa P25) in terms of degradation of Reactive Blue (RB-19) dye. The photocatalysis was favoured under initial acidic pH, and complete degradation of 50 mg/L dye could be achieved at optimum catalyst loading of 1 g/L. The kinetics of degradation followed the Langmuir-Hinshelhood model. PANI-TiO₂ nanocomposite showed almost similar photocatalytic activity under UV and visible light as well as in the solar light which comprises of radiation in both UV and visible light range. Chemical oxygen demand removal of 86% could also be achieved under visible light, confirming that simultaneous mineralization of the dye occurred during photocatalysis. PANI-TiO₂ nanocomposites are promising photocatalysts for the treatment of industrial wastewater containing RB-19 dye.

Stable plasmonic Ag/AgCl–polyaniline photoactive composite for degradation of organic contaminants under solar light

A series of novel plasmonic photocatalysts of Ag/AgCl–polyaniline (Ag/AgCl–PANI) were successfully synthesized by deposition–precipitation reaction followed by a photo-reduction method.

Green and low-cost synthesis of PANI–TiO2 nanocomposite mesoporous films for photoelectrochemical water splitting

Green and low-cost synthesis procedure for preparation of PANI/TiO₂ mesoporous nanocomposite films with enhanced photocatalytic performance, thanks to a synergic reaction mechanism between PANI and TiO₂ under UV light irradiation.

Preparation of conductive polyaniline grafted graphene hybrid composites via graft polymerization at room temperature

Graphene was covalently functionalized with phenol groups via a 1,3-dipolar cycloaddition reaction without degrading its electronic properties.

Loading of PPy on the surface of transition metal coordination polymer modified polyoxometalate (TMCP/POM): a feasible strategy to obtain visible light active and high quantum yields POM based photocatalyst

PPy loaded TMCP/POM composite materials were fabricated successfully and display better photocatalytic activity than TMCP/POM under visible light irradiation.

Syntheses and optoelectronic properties of amino/carboxyphenylporphyrins for potential use in dye-sensitized TiO2 solar cells

New mixed-substituent amino/carboxyphenylporphyrins for a dye-sensitized TiO 2 solar cell were prepared using several synthetic routes. The reaction of 4-carbomethoxy- and 4-acetamidobenzaldehydes with pyrrole in propionic acid under aerobic conditions afforded mixtures of mixed amide/ester substituted tetraphenylporphyrins which were separated using centrifugal chromatography then deprotected to give the target compounds. Condensation of p-nitrophenyldipyrromethane with 4-carbomethoxybenzaldehyde in CH 2 Cl 2 catalyzed by trifluoroacetic acid, followed by oxidation with dichlorodicyanoquinone gives trans-dicarbomethoxy/dinitrophenylporphyrin, which when treated with SnCl 2 and HCl affords the trans-diamino/dicarboxy derivative, trans- TA 2 C 2 PP . Commercially available tetrakis-5,10,15,20-(4-carboxyphenyl)porphyrin (TCPP) was converted to mixtures of mixed amino/carbomethoxyphenylporphyrins using hydroxylamine hydrochloride in polyphosphoric acid with methanol workup. Relative yields and product distributions from each route are discussed and the optoelectronic characteristics of the synthesized porphyrins were studied using UV-visible spectroscopy and cyclic voltammetry.

Preparation and antibacterial activities of polyaniline/Cu0.05Zn0.95O nanocomposites

Polyaniline/Cu(0.05)Zn(0.95)O (PANI/CZO) nanocomposites were prepared by in situ inverse microemulsion method. Based on the characterization of the crystal structure, chemical composition, and morphology of the samples, it was confirmed that CZO nanoparticles were incorporated into the polyaniline matrix. Studies of the antimicrobial activities of the samples against Staphylococcus aureus, Escherichia coli and Candida albicans were carried out using powder inhibition zone, minimum inhibitory concentration and minimal bactericidal concentrations methods. The results showed clearly that, as an antibacterial agent, PANI/CZO nanocomposites exhibited excellent antibacterial activity against the growth of microorganisms. Furthermore, the antibacterial mechanism of the samples was also deduced in this paper.

Self-assembled monolayers and titanium dioxide: From surface patterning to potential applications

The ability to control the properties of self-assembled monolayers (SAMs) attached to solid surfaces and the rare photocatalytic properties of titanium dioxide provide a rationale for the study of systems comprising both. Such systems can be realized in the form of SAMs grown on TiO(2) or, in a complementary manner, as TiO(2) grown on SAMs. Accordingly, the current status of knowledge regarding SAMs on TiO(2) is described. Photocatalytic phenomena that are of specific relevance to SAMs, such as remote degradation, and cases where SAMs were used to study photocatalytic phenomena, are discussed as well. Mastering of micro-patterning is a key issue en route to a successful assimilation of a variety of titanium dioxide based devices. Accordingly, particular attention is given to the description of a variety of methods and techniques aimed at utilizing the photocatalytic properties of titanium dioxide for patterning. Reports on a variety of applications are discussed. These examples, representing the areas of photovoltaics, microelectronics, microelectromechanics, photocatalysis, corrosion prevention and even biomedicine should be regarded as appetizers paving the way for further studies to be performed.

Preparation of Polyaniline Supported TiO2 Photocatalyst and its Photocatalytic Property

A polyaniline supported titanium dioxide photocatalyst was prepared by an impregnation-hydrothermal process and characterized by powder X-ray diffraction, transmission electron microscopy and UV-visible spectroscopy. It was found that the TiO2 nanoparticles were well dispersed on the surface of the polyaniline and the photocatalyst has a stronger absorption compared with that of pure TiO2 over the whole of the visible spectrum. The photocatalyst exhibited higher photocatalytic activity than pure TiO2 for the photodegradation of solutions of the anthraquinone dye, reactive brilliant blue KN-R, under visible light irradiation.

Controlling surface functionality through generation of thiol groups in a self-assembled monolayer

A lithographic method to generate reactive thiol groups on functionalized synthetic diamond for biosensor and molecular electronic applications is developed. We demonstrate that ultrananocrystalline diamond (UNCD) thin films covalently functionalized with surface-generated thiol groups allow controlled thiol-disulfide exchange surface hybridization processes. The generation of the thiol functional head groups was obtained by irradiating phenylsulfonic acid (PSA) monolayers on UNCD surfaces. The conversion of the functional headgroup of the self-assembled monolayer was verified by using X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS), and fluorescence microscopy. Our findings indicate the selective generation of reactive thiol surface groups. Furthermore, we demonstrate the grafting of yeast cytochrome c to the thiol-modified diamond surface and the electron transfer between protein and electrode.

Enhanced protein immobilization efficiency on a TiO2 surface modified with a hydroxyl functional group

An antibody immobilization was investigated using a self-assembled monolayer (SAM) over the highly refractive coatings with a SiO2, TiO2, or Si3N4 substrate. The immobilization was characterized by analyzing the hydrophilic properties of hydroxyl (OH) groups on surface coatings with contact angle (CA) measurements to enhance protein immobilization. The hydroxyl (OH) group was formed in greater amounts as the oxygen plasma exposure time was increased, which resulted in a large enhancement in antibody immobilization. It indicated that hydroxyl (OH) group formation is critical for developing a label-free optical transducer with a high sensitivity.

Photoelectropolymerization of aniline in a dye-sensitized solar cell

A dye-sensitized solar cell was constructed using a porphyrin photosensitizer and, in place of the usual iodide redox system, a solution in aniline solvent containing lithium perchlorate electrolyte, camphorsulfonic acid, and poly(ethylene oxide) copolymer. Irradiation generated polyaniline within the cell, initially following a proposed photoelectropolymerization mechanism, and eventually operating as a solar cell with polyaniline as the hole transport medium. Overall energy conversion efficiency was 0.8% at moderate light intensities (14.6 mW cm(-2)) but lower at higher light intensities due to conductivity limitations.