FUNCTIONALIZED DNA THIN FILMS

Physico-Chemical Characterization of Polypyrrole Film Grown in Aqueous and Non Aqueous Solution on Different Substrates

Poly(naphthalenediimidequaterthiophene):Poly(hexyilthiophene) Heterojunctions. Efficient Polymer-to-Polymer Electron Transfer Interfaces

Organic thin films solar cells and plastic solar cells [1] have attracted the attention of the scientific community especially as regards the performance of new conjugated polymers including their interfaces [2-4]. In this work, poly(naphthalenediimidequaterthiophene) (PNDIT4) and poly(hexyilthiophene) (P3HT) have been employed, for the first time, for engineering planar and bulk heterojunctions by the synergetic use of two techniques: electropolymerization and layer by layer deposition. Electropolymerization has been used for obtaining PNDIT4 thin films on transparent ITO/PET electrodes, starting from the synthesized monomer. Inverse Langmuir-Schaefer technique has been employed for deposi…

Point-Of-Care Plastic Biosensor Devices using a PEDOT-modified Electrochemical Glucose Sensing Platform

There is an emerging global epidemic of diabetes that can be related to rapid increases in overweight, including obesity and physical inactivity. According to World Healthcare Organization, diabetes is a leading cause of blindness, amputation and kidney failure, while total deaths from diabetes are projected to rise by more than 50% in the next 10 years. To prevent life threatening and debilitating complications associated with diabetes, researchers are continuously involved in developing glucose biosensors. Hence, it is essential to develop a biosensor that can determine glucose levels having fast-response, high sensitivity and selectivity. Depending upon the transduction technique, a numb…

ELECTROCHROMIC PERFORMANCE OF A NOVEL POLY(NAPHTHALENEDIIMIDEQUATERTHIOPHENE)

Conjugated polymers (CP) display several interesting properties which enable them their application in different fields such as solar cells, light emitting diodes, field effect transistors, electrochromic devices to cite a few. One of the most interesting properties of this class of materials is their ability of switching from a conductive to an insulating state and vice versa by changing their redox state. The possibility to switch from an oxidized to a neutral or reduced state induces variations of the optical spectrum due to changes in the electron excitation energy configuration resulting in electrochromism. Nowadays, electrochromic conjugated polymers are stimulating the development of…

Photoelectrochemical Characterization of Ta/Ta2O5/Polypyrrole Heterojunctions

A photodeposition of polypyrrole on anodic tantalum oxide thin films was performed in both organic and aqueous media. Pyrrole was photo-oxidised on insulating tantalum oxide by irradiating the electrode with light of suitable energy. Tantalum/ tantalum oxide/ polypyrrole heterojunctions were then characterized by means of photocurrent spectroscopy. The comparison between the photoelectrochemical response of the heterojunctions fabricated in organic and aqueous media, shows that the solvent used for the photodeposition of polypyrrole influences the location of the inversion potential. This result can be attributed to the different structure of polypyrrole films, which strongly depends on the…

Assembly of a polyoxometalate supported {V6} core and integration into a functional material for energy applications

Polyoxometalate – rich thin films with controlled structure and function for designer electronics

During the last two decades, polyoxometalates (POMs) have attracted growing attention due to their potential application as functional materials potentially enabling new device design and opening new areas of technology. POMs are metal-oxide clusters of early transition metals Mo, W, V, etc with a diverse range of structures and properties, such as reversible electrical capacitance,[1] programmable surface 0D, 2D or 3D structure[2] which could together be of potential application in ultra-high-density data storage,[3],5 catalysis[4] and also in medicine as antiviral drugs.[5] In the present work, we show that it is possible to assemble structured thin-films by the self-assembly/organization…

Physico-Chemical Characterization of Ta2O5 Thin Films/Electrolyte Junctions

An analysis of the electronic properties of Ta2O5 / electrolyte junction is reported for thin film (≤ 14 nm) grown on tantalum in acidic electrolyte. The investigation is carried out by the synergetic use of three techniques: Photocurrent Spectroscopy (PCS), Electrochemical Impedance Spectroscopy (EIS) and Differential Admittance (DA) measurements. PCS is a non destructive optical technique based on the analysis of the electrochemical response (photocurrent or photopotential) of the electrode/electrolyte interface under irradiation with photons of suitable energy. PCS can provide information on the energetic of metal/oxide/electrolyte interfaces (flat band potential determination, conductio…

Controlled 3D Interfacing of Three Components Thin Films for Photovoltaics

One of the main problems related to the low performance of the organic photovoltaic (OPV) devices, concerns the low mobility of the materials forming the heterojunction. For this reason, there is competition between the sweep-out and recombination of the photogenerated carriers within the thin film bulk heterojunction (BHJ). To overcome this problem, it is usual to operate by reducing the thickness of the active layer, so that the recombination of charge carriers is inhibited. This choice, however, also translates into a lower absorption of light by the active film itself. Plasmonic structures allow to reduce the "physical" thickness of heterojunction, maintaining constant the "optical" thi…

Investigation of NLO Properties of some Selected Polythiophenes Electrodeposited on ITO Glasses

Photocurrent and Impedance Spectroscopy Studies on Electrodeposited Polypyrrole

Fabrication of MIM and MIS Structures for Organic Electronics

Symmetric Naphthalenediimidethiophene Systems for Electrochromic Devices

Poster Presentation

ELECTROPOLYMERIZATION OF NOVEL BENZOFULVENES FOR FLEXIBLE ELECTROCHROMIC DEVICES

Characterization and Investigation of NLO Properties of some Selected Electrodeposited Polythiophenes

In this work we study the electronic properties of ClO− doped polythiophenes and discuss the nonlinear optical properties of these organic 4 compounds galvanostatically electrodeposited on ITO glasses. The investigation on the electronic properties (band gap, flat band potential) was performed by means of a non-destructive optical technique, photocurrent spectroscopy (PCS). The investigation on the nonlinear optical response was carried out by means of second and third harmonic generation (SHG and THG) measurements. In particular, the effect of the oxidation state of the polymeric films was studied by comparing the NLO response of oxidized and reduced polythiophenes. Reduced poly- meric films …

Photoelectrochemical Characterization of Polypyrrole Electrodeposited in Aqueous and Non-Aqueous Solutions

Steady State Fluorescence Studies on Electrodeposited ZnO-Based Heterojunctions

ORGANOTIN(IV)-PORPHINATE FOR PHOTOVOLTAIC BULK HETEROJUNCTIONS

Due to the versatility and variability of their molecular structures, optical spectra, electrical properties, and supramolecular organization potential, porphyrins related compounds have been widely studied in organic solar cells [1,2]. Indeed, these applications are a natural function for these compounds, and they have been extensively investigated in a variety of formats including single molecules, macromolecular and supramolecular structures. In this work, poly(hexylthiophene) (P3HT) and organotin(IV)-[meso-tetra(4-carboxyphenyl) porphinate] have been employed for engineering planar and bulk heterojunctions by layer by layer deposition. Improving the overall efficiencies of photovoltaic …

3D ORGANIZATION OF THIN FILMS FOR THREE COMPONENTS ACTIVE LAYER IN PHOTOVOLTAIC DEVICES

Polymer-fullerene or polymer-polymer based bulk heterojunction (BHJ) solar cells can be fabricated by using low-cost manufacturing methods. However, because of the low mobility of organic materials, there is a competition between separation and recombination of the photogenerated carriers within the thin BHJ film. Thus, there is a need to develop strategies to increase light harvesting in the films without increasing the film thickness. Nanoparticles (NPs) have been receiving a lot of interest for exhibiting interesting optical, electrical, and magnetic properties. These novel properties can be exploited in nanotechnology by forming compact and ordered architectures of nanoparticles within …

Structural, Superficial and Optical Properties of Nanostructured Polycrystalline ZnO:X (Cu, Ag) Films

Influence of Ag, Cu dopants on the second and third optical harmonic generation of ZnO films

Third order nonlinear optical properties of novel TetrathiafulvalenePhenanthroline based dyads

The non-linear optical properties of π-conjugated organic molecules such as TTF and their derivatives have recently gained particular interest due to their extended π-system and the strong electron donating character. The knowledge of the nonlinear optical response, as well as the impact of the charge transfer on the nonlinearity is very important. As such systems can be used in a variety of applications. In this study we investigate the nonlinear absorption of novel tetrathiafulvalene-phenanthroline based dyads by means of the Z-scan technique.

Photoelectrochemical Synthesis of Conducting Polymers on Large Band Gap Nb2O5 and Ta2O5 Anodic Oxide Films

Photoelectrochemical Synthesis of Conducting Polymers Layers on Large Band Gap Nb2O5 and Ta2O5 Anodic Oxides Films

Electrochemical growth and physico-chemical characterization in organic medium of Nb2O5 thin films

Investigations about the energetics and the electrical properties of niobium thin film, electrochemically grown, were performed in an organic solution of acetonitrile and lithium perchlorate. The study of the energetics of the Nb O /organic solution interface was performed by means of a non-destructive optical technique, photocurrent 2 5 spectroscopy. By means of this technique, it was possible estimating the value of the flat band potential and locating conduction and valence band. A more cathodic value of flat band potential in respect with acidic solution was found in organic medium. From impedance spectra, the electrical circuit that gives best fitting values is constituted by two resis…