A5053268258- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Organic Light-Emitting Diodes Research
- Molecular Junctions and Nanostructures
- Advanced Sensor and Energy Harvesting Materials
- Semiconductor materials and interfaces
- Perovskite Materials and Applications
- Gas Sensing Nanomaterials and Sensors
- Carbon Nanotubes in Composites
- Nanowire Synthesis and Applications
- Analytical Chemistry and Sensors
- Fullerene Chemistry and Applications
- Silicon Nanostructures and Photoluminescence
- ZnO doping and properties
- Photochemistry and Electron Transfer Studies
- Thin-Film Transistor Technologies
- Force Microscopy Techniques and Applications
- Quantum Dots Synthesis And Properties
- Polymer Nanocomposite Synthesis and Irradiation
- Electron and X-Ray Spectroscopy Techniques
- Nanomaterials and Printing Technologies
- Ion-surface interactions and analysis
- Green IT and Sustainability
- Semiconductor materials and devices
- Transition Metal Oxide Nanomaterials
Universidade Federal do Paraná
2016-2025
Quantum Devices (United States)
2025
Materials Science & Engineering
2024
Centro Universitário Curitiba
2015-2020
Instituto Politécnico Nacional
2020
Universidade Federal do Rio de Janeiro
2019
Universidade Tecnológica Federal do Paraná
2013
Brazilian Synchrotron Light Laboratory
2006
Universidade Estadual de Campinas (UNICAMP)
2006
Linköping University
1997-2003
We have modeled experimental short-circuit photocurrent action spectra of poly(3-(4′-(1″,4″,7″-trioxaoctyl)phenyl)thiophene) (PEOPT)/fullerene (C60) thin film heterojunction photovoltaic devices. Modeling was based on the assumption that generation process is result creation and diffusion photogenerated species (excitons), which are dissociated by charge transfer at PEOPT/C60 interface. The internal optical electric field distribution inside devices calculated with use complex indices...
Which factors affect the device efficiency of PEOPT/C60 photodiodes (where PEOPT is a polythiophene derivative) most strongly? In order to answer this question, performance five-layer sandwich structure with different layer thicknesses has been studied. It shown that strongly connected geometry and optical field distribution rather than quantity active material. Optimization thickness both C60 polymer electrode can enhance performance.
Abstract The synthesis and characterization of thin films polyaniline/carbon nanotubes nanocomposites is reported, as well their utilization transparent electrodes in ITO‐free organic photovoltaic devices. These are generated by interfacial synthesis, which provides them with the unique ability to be deposited onto any substrate films, thus enabling production flexible solar cells using substrates like PET. Very high carbon nanotube loadings can achieved these without significantly affecting...
We attempt to reconcile experimental and theoretical methodologies for the determination of energy gap, which is essential properly characterize a series key phenomena related applications organic semiconductors.
Highly efficient photovoltaic devices , constructed using polythiophene derivatives blended with fullerenes, are described. The behavior of the sandwich‐structure (current‐voltage characteristic, conversion efficiency) is reported and electrical, optical (optical absorption, photoluminescence), morphological properties blends presented. importance morphology films pointed out: it can determine devices.
The patterning of polymer-based semiconductors, conductors, and insulators using photoresists is compromised because the chemical vulnerability polymers towards etching photopatterning steps. Here an approach to preparation polymer LEDs soft lithography techniques based on elastomer stamps presented. Figure shows line-shaped produced by microcontact printing.
Increasing the conversion efficiency is very important in photovoltaic devices, as cheap and simple technology. Here demonstrated a soft embossing technique for printing submicrometer grating with an elastomeric mold into optically active polymer layer device (see Figure). The light trapping due to pattern enhances photoconversion by more than 25 % at normal incidence also inside front cover).
Polymer diodes made using a bilayer of doped poly(3,4-ethylenedioxythiophene) and semiconducting polymer in sandwich structure with two low-work-function metals are reported. The conducting layer acted as modifier the injection properties metal, allowing easy hole injection. Upon insertion layer, contact-limited current flow became bulk limited. With this anode, fabrication rectification ratio seven orders magnitude was possible. We present patterned microdiodes crossing 10 μm lines, showing...
Novel silver nanoparticles/polyaniline composites were obtained through a two-phase water/toluene interfacial reaction. We show that by rigorously controlling the reaction time, different structures of nanocomposites can be obtained, such as thin sheet polyaniline around nanoparticles or polymer mass with homogeneously embedded within it. Samples characterized FT-IR, UV−vis−NIR and Raman spectroscopy, X-ray diffraction, cyclic voltammetry, TEM, HRTEM. Conductivity current−voltage...
This study presents a simple and cost-effective approach for synthesizing pyrolytic lignin-based carbon dots (CDPLs) via controlled thermal pyrolysis in water. To the best of our knowledge, this is first time that lignin has been used as precursor dots. The one-pot method produced blue/green fluorescent CDPLs with an average size 34 nm negative surface charge -10.4 mV. characterization techniques revealed optical properties chemical composition CDPLs, fluorescence quantum yield 7.9%, which...
We present an analysis of the internal monochromatic quantum efficiency photovoltaic devices based on polymer and polymer/fullerene thin films. A exciton-to-charge generation is defined as external normalized to absorption in active materials device. An upper limit can be determined, results show that much light absorbed photoactive layers device, whereas only a fraction generated excitons converted charge carriers collected photocurrent.
Abstract Objective: An important characteristic of human dental enamel not yet studied in detail is its surface roughness mesoscopic scale. This study evaluated quantitatively and qualitatively the topography acid etched with different etching times. Materials Methods: Ninety-six maxillary bicuspids were randomly distributed into three groups (n=32): T0 (control), pumiced; T15, 35% phosphoric for 15 s; T30, 30 s. Roughness measurements Ra, Rz root mean square (RMS) 3D images enamel′s...
By combining experimental and theoretical approaches, the electronic structure, molecular orientation, charge transfer dynamics solar cell performance in donor/acceptor copolymer poly[2,7-(9,9-bis(2-ethylhexyl)-dibenzosilole)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PSiF-DBT) films blended with 6,6.-phenyl-C 61-butyric acid methyl ester (PSiF-DBT:PCBM) were investigated. Good agreement between PSiF-DBT UV-Vis absorption spectrum is observed main orbitals contributing to determined...
A versatile and room temperature synthesis of thin films polymer/graphene is reported. Drastically differing from other methods, not only the polymer but also graphene are completely built their simplest monomers (thiophene benzene) in a one-pot polymerization reaction at liquid-liquid interface. The materials were characterized electronic properties presented.
Abstract In this work we propose an easy method to achieve a conductive, transparent and flexible graphene oxide (GO)-based composite thin film from aqueous dispersion. We investigated the blend ratio between GO conjugated polymer poly(3,4–ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) by comparing optical transmittance, sheet resistance, morphology mechanical stability. It was found that reasonable values of transmittance resistivity coupled with its excellent flexibility –...