Bruno Cucco

Phd Candidate

Organization:
Institut des Sciences Chimiques de Rennes - UMR CNRS 6226
Address:

Université de Rennes 1 - Campus de Beaulieu - Bât. 10B

Locality:

Rennes 35700

France

Email : bruno [dot] cucco [at] univ-rennes1 [dot] fr

Office number : 213

Research theme

I am a theoretical physicist investigating new promising materials for photovoltaic applications with particular focus on perovskite like crystalline structures. My research is conducted within state of art quantum modelling approach's such as density functional theory (DFT), GW method and tight-binding wannierization methods.

Below you'll find a "motivational" discussion of this research:

 

The Energy Crisis: An Overview and Possible Solutions

Every year the global energy demand becomes higher as the population increases and new non-green technologies arises. Also, alongside this energetic crisis a climate catastrophe is also eminent. The term “Climate-change“ still a topic of immense debate nowadays, even when there are an overwhelming and indisputable amount of evidence which associates the global warming to the augmented anthropogenic greenhouse gas emissions, such as CO2, mainly due to the energy demand being supplied by burning of fossil fuels.

                     Figure 1 - Data from Smil (2010). Credit: David Bice

Such increase, not surprisingly, started around the years 1760-1840 during the industrial revolution which led humanity to consume various different non-renewable energies sources, as can be seen at figure 1. These ones, like fossil fuels, releases the so called CO2 during the burning process. Unlike most components of our atmosphere such as Nitrogen and Oxygen, greenhouse gases such as the carbon dioxide absorbs the natural sunlight thermal energy and gradually releases it as heat over the planet. This characteristic associated to the fact that these gases absorb wavelengths that water vapor does not, plus its abundance on the planet atmosphere turns it into one of the main mechanisms of global heating nowadays. Of course the concentration of carbon dioxide on the atmosphere has also been shown to increase on the past 50 years as can be seen at figure 2 on the left, and as result so do the global temperature at figure 2 on the right. In fact as recent research shows, through the last 100 years the global warming has never stopped at all, exhibiting a peek soon after the World War 2 and a constant rate of 0.08oC/10a after that.

Unfortunately the problems are far more complicated than that and causes a huge chain of reaction on the planet fauna and flora. The first immediate consequence is the large increase of sea level related to the melting of polar ice caps due to global warmth, which will directly affect several coastal areas around the globe and a also a whole bioma. The second one is that all this carbon dioxide eventually dissolves into the ocean. In this process it reacts with water molecules producing carbonic acid, lowering the ocean’s pH. This ocean acidification not only directly affects the marine life but also our own, weakening the phytoplankton and their ability to produce oxygen.

 

                                                 Figure 2 - NOAA's Mauna Loa Observatory carbon dioxide data on the left. Paper DOI:10.1038/s41598-018-31862-z on the right.

 

Its clear that new energy sources are needed not only to control the mentioned effects on our planet but also to supply the future generations, since all these main harmful sources are natural and more scanty each year. As so, there is a global effort between researchers to find suitable renewable options both environmental and financially speaking, for example nuclear, solar and geothermal energies.

Between these the solar energy is by far the most abundant one with a huge source right above our heads. Solar cell’s as a mean to extract solar energy has been showing great promises with outstanding performances increases every year. At time of writing the solar energy is already the most cheapest form of energy generation in more the 16 US states, Spain, Italy and India, and its cost is expected to lower even more through the next years. On the NREL plot below its illustrated the advances on the efficiencies of solar cell’s along the past few years.

Between these a very interesting class of materials arises on the “Emerging PV” scenario marked in red lines and yellow dots on this chart, the Perovskite solar cells. This interesting and promising class of materials are my main research interest at the moment and they are discussed a little bit more on the following section.

 

References:

“Identifying the early 2000s hiatus associated with internal climate variability”, Dai X., Wang P. - Nature Scientific Reports. (2018) 8:13602 | DOI:10.1038/s41598-018-31862-z

Woods Hole Oceanographic Institution. (2015). Introduction to ocean acidification. Accessed October 4, 2017.

Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T.F. Stocker. (2008). High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature, Vol. 453, pp. 379-382. doi:10.1038/nature06949.

Collins, M., R. Knutti, J. Arblaster, J.-L. Dufresne, T. Fichefet, P. Friedlingstein, X. Gao, W.J. Gutowski, T. Johns, G. Krinner, M. Shongwe, C. Tebaldi, A.J. Weaver and M. Wehner, 2013: Long-term Climate Change: Projections, Commitments and Irreversibility. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

X. Lan, B. D. Hall, G. Dutton, J. Mühle, and J. W. Elkins. (2020). Atmospheric composition [in State of the Climate in 2018, Chapter 2: Global Climate]. Special Online Supplement to the Bulletin of the American Meteorological Society, Vol.101, No. 8, August, 2020. 

Perovskite Materials for Photovoltaic

Between the various classes of materials present on the NREL chart, the ABX3 perovskites have emerged as extremely promising materials for photovoltaic technology due to their rapidly increasing power conversion efficiencies and low processing cost. Between them the lead-based halide perovskites CsPbX3 (X=Cl, Br, I) has exhibited incredible results in terms of efficiency even at single junction level, the correspondent high-temperature cubic phase it represented on the left of the figure below. Although they are indeed very promising the concern regarding their stability and the toxicity related to lead still a problem to be concerned. Its already well known that this materials exhibit stability problems against moisture, heat and prolonged exposure to light, which when degraded releases lead based compounds on the environment that can rapidly spread across soil and water. Hence, the research for lead-free perovskite materials that can exhibit both stability and high efficiencies still a very hot topic on the literature.

                                                                                                      Figure extracted from the reference J. Phys. Chem. Lett. 2016, 7, 7, 1254–1259

A very promising candidate to contour this problem is the so called double perovskites, which structure reassembles the traditional one as illustrated at the figure above on the right. Here we have the heavy metal cations Pb2+ being replaced by a monovalent and one trivalent cation in order to maintain charge neutrality, giving rise to a lead-free checkerboard like crystalline structure. From the double perovskite we can also derive other different materials like the vacancy ordered perovskites and so on. Every year the family of “perovskitoid” like materials grows more and more opening a wide angle of investigation in both theory and experimental areas.

Here we make use of state of art theories and techniques such as the density functional theory, GW method and alloying techniques to theoretically investigate the structural and electronic properties of these materials. Understanding the mechanisms underlying its physical properties it's possible to predict and designing novel promising materials for photovoltaic applications with desirable and controllable properties. Which via collaborations can also be experimentally investigated.

 

Skills & Interests

▪ Physical properties of materials for photovoltaics
▪ Ab initio methods for materials modelling
▪ Topological properties of quantum matter
▪ Many-Body Perturbation Theory


Ab initio codes: 
▪ Quantum-Espresso
▪ OpenMX
▪ VASP
▪ YAMBO
▪ Wannier90
▪ WannierTools

Education

2020 - Now | PhD
Institut des Sciences Chimiques de Rennes (Rennes, France)
Université de Rennes 1
Advisors: Dr. Mikaël Kepenekian (CNRS Researcher) & Dr. George Volonakis (Rennes Métropole Chair)
Title: 'Computational design of novel 2D perovskite materials for energy applications: Electronic structure and Interfaces from first-principles'

2018 - 2020 | Master Degree on Physics
Instituto de Ciências Exatas (Belo Horizonte, Brazil)
Universidade Federal de Minas Gerais
Advisors: Dra. Simone Silva Alexandre (Associate Professor) & Dr. Raphael Longuinhos Monteiro Lobato (Associate Professor at UFLA)
Title: 'Study of Topological Insulators Derived from Jacutingaite'

2014 - 2018 | License Degree on Physics
Centro de Ciências Físicas e Matemáticas (Florianópolis, Brazil)
Universidade Federal de Santa Catarina