Research
My research contributions are related to the steps in my career in the fields of organic electronics, photovoltaic devices, chaotic systems and circuits. My research primarily focuses on organic and hybrid organic/inorganic electronics, mainly the fabrication and characterization of electronic and optoelectronic devices as solar cells, photodetectors, LEDs, transistors and sensors. In general, my interest goes from the processing of semiconductor films, the understanding of material and transport properties and the fabrication of innovative high performing devices. I also develop and use computational routines in the study of electronic circuits and its chaotic pattern recognition and estimation, including the data processing and analysis of large datasets. Last, my mechanical aptitude and experience motivates me to research ways to improve laboratory machinery and procedures with the aim to upgrade fabrication and characterization techniques and routines.
Organic Electronics and Solar Cells
In my Ph.D. research, I worked in the Group of Organic Optoelectronic Devices, under supervision of Prof. Ivo A. Hümmelgem. This was an experimental research with organic and inorganic solar cells. I have contributed to the research on solar cells and particularly in the application of Selenium and Selenium-based alloys in photovoltaic devices, highlighting the effects of adding different materials to the morphological and optical characteristics of Selenium in the fabrication of thin films. The obtained results explained the functionality of a simple structure, and how the film morphology and charge transfer to the electrodes is modified in a way that its power output is improved in consequence of the gallium. For the first time, careful analyses of capacitance-voltage and impedance spectroscopy were performed for Selenium-based solar cells, and I identified the recombination process that limits its efficiency and possible ways to overcome it. This work was a mix between theory and experimental, and the results are published in the following papers:
Morphological, optical and electrical properties of GaSe9 films and its application in photovoltaic devices
Journal of Materials Science: Materials in Electronics - 2017
Influence of an interfacial cesium oxide thin layer in the performance and internal dynamic processes of GaSe9 solar cells
Solar Energy Materials and Solar Cells - 2017
Enhancement of P3HT organic photodiodes by the addition of a GaSe9 alloy thin layer
Semiconductor Science and Technology - 2017
GaxSe10-x based solar cells: Some alternatives for the improvement in their performance parameters
Solar Energy Materials and Solar Cells - 2019
Electronic Circuits and Chaos Theory
I started my research in Chaos Theory during my Master’s degree, and after in my postdoctoral research, both under supervision of Prof. Holokx A. Albuquerque. My research was related to chaos theory and time series analysis. Particularly, I worked with bifurcation curves and Lyapunov exponents in chaotic dynamical systems. My research contributed to the understanding of the chaotic behaviour on electronic systems, from both numerical and experimental approaches. Besides, the employment of different tools gave detailed information regarding the connection between different analyses and how to combine them in parameter-spaces.
The following papers resulted from these researchs:
Bifurcation structures and transient chaos in a four-dimensional Chua model
Physics Letters A - 2014
Numerical bifurcation analysis of two coupled FitzHugh-Nagumo oscillators
The European Physical Journal B - 2014
Extensive numerical study and circuitry implementation of the Watt governor model
International Journal of Bifurcation and Chaos - 2017
Furthermore, on my Postdoctoral research I worked with time series analysis and assembling analogic electronic circuits to study the chaotic behavior of systems under different parameters, and correlating the results with numerical simulations.
For the first time, we applied the 0-1 Test for Chaos to characterize the behavior of electronic systems in the parameter-space of dynamical systems, identifying the pattern behaviour by its time series analysis. The first results are published on International Journal of Bifurcation and Chaos. To achieve it, I developed programming routines in R to automate the numerical procedure for big datasets, which are being applied by other students from the research group in their analyses of numerical and experimental chaotic systems. These routines are available in my GitHub account.
Some interesting results are still to be published. Other results were published and are listed below.
Tracking multistability in the parameter space of a Chua’s circuit model
The European Physical Journal B - 2019
Characterizing the Dynamics of the Watt Governor System Under Harmonic Perturbation and Gaussian Noise
International Journal of Bifurcation and Chaos - 2020
Particularly, the last publication is a Featured Article, and the cover of International Journal of Bifurcation and Chaos 30-01, which I share below.
