Research

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Semiconductors

Semiconductors are materials with bang-gap between 1.0 and 4.5 eV, being important to the development of several technological devices. In this area, the most prominent candidates are simple oxides (ZnO, TiO2, ZrO2), perovskites (PbTiO3, BaTiO3, SnTiO3, CaTiO3), ilmenites (MgSiO3, ZnTiO3). These compounds are applied to transparent conductive walls, dielectric-ferroelectric systems, thermistors, and others. Our group focus on the structural, electronic, elastic and dielectric/ferroelectric investigation of such materials using throughput DFT calculations. Indeed, the main advances are related to the ferroelectric/paraelectric phase transition description, doping effects on electrical and optical properties, as well as structural stability under pressure.

Conductive polymers and organic materials

Conductive polymers allow excellent control of the electrical stimulus, possess very good electrical and optical properties, have a high conductivity/weight ratio and can be made biocompatible, biodegradable and porous. Such amount of properties enables a vast number of technological application’s, mainly due to the tailoring of chemical and physical behavior through doping, synthesis or stimulation. Regarding the computational studies of these materials, we are focusing on materials for solar cells using both conductive polymers, as well others organic semiconductors. For instance, remarkable advances have been made on TDDFT calculations to investigate UV-VIS spectra, intra- and intermolecular charge transfer effects of PEDOT, PPy, PTh, PPV and PANI. Furthermore, recent studies also investigate the electronic structure of radicals, chromophore’s, as well as electrochemical mechanism at metal substrates and aqueous solutions.

Graphene-based materials

The graphene particles as graphene oxide (GO), graphene few layers (GFL), pure and doped graphene (GF) have been extensively studied currently in the literature mainly due to the mechanical strength, high carrier mobility, optical transmittance, luminescence, low density, and high surface area. In this research topic, we are developing studies to understand the exfoliation mechanism to obtain graphene oxide from graphitic materials jointing experimental and theoretical efforts. Further, we also study graphene composites (MnO2-GO, ZnO-GO) for electrical and photocatalytic applications. Another research topic is related to the ion intercalated graphitic compounds, such as LiC6, focusing on the understanding and development of new candidates for batteries.

Group of Chemical Simulation (GSQ) from Ponta Grossa State University - Theoretical investigation on Materials Chemistry

Multiferroic materials

Recently, the multiferroics materials have assumed remarkable importance as a research topic on the design of new technological devices. Such compounds combine two or more forms of ferroic orders (i. e. ferroelectricity, ferroelasticity, ferromagnetism, ferrotoroidicity) into a single crystalline structure, being responsible to control the magnetic ordering of a material with an electric field, an enticing prospect for device engineering. Several physical and chemical requirements are needed to enable the multiferroic application, such as the magnetoelectric effect. In this field, we are involved in the clarification of common and unusual phenomena observed for LiNbO3-type structures, such as FeTiO3, MnTiO3, FeSnO3, PbNiO3, BiFeO3. Furthermore, our ongoing projects also focus on the prediction of new candidates with superior electrical, magnetic, optical and dielectric properties.