Demétrio A. da Silva Filho

Presentation - Demétrio Filho is a professor of Physics at the University of Brasilia and is the head of the department of Materials Structure, in the Institute of Physics. His research focus in the transport properties of Organic Semiconductors. He has published more than 70 scientific papers that currently has been cited more than 11.000 times. He finished his PhD at the University of Campinas with a research stay at The University of Arizona (USA). After his post-doc at the Georgia Institute of Technology, he has been Senior Research Scientist at the same institution in the group of Prof. Jean-Luc Brédas. He is now full professor at the University of Brasilia. 

Research project - One of today's big challenges to material scientists is how to make cheaper and more efficient photovoltaic panels. Three-dimensional (3D) perovskite solar cells (PSC) emerged in 2009 and, with unprecedented growth of efficiency (from 3.8% to 21.8%), have attracted the attention of both academia and industry. Current research is focused on the two biggest challenges concerning the PSC: increasing their stability and reducing their toxicity. Here we propose a research project that will combine our expertise on organic semiconductors to apply state-of-the-art theoretical models in the description of the electronic structure and the nature of an exciton in a two-dimensional (2D) analogy of the 3D hybrid perovskites. Our research project takes advantage of the theoretical expertise of our group, in the theoretical characterization of excitons and their dynamics in organic materials and the expertise of Dr. Sini’s group at the University of Cergy-Pontoise in the spectroscopic signature of these quasi-particles to draw a comprehensive picture of the phenomena of light absorption and charge separation in these devices. Once a model is developed and validated, we will use it to investigate the impact of the substitution of the lead atom by other atoms, in the search for a solution to the above-mentioned toxicity problem. By understanding the nature of an exciton, we will be able to propose 2D structural modifications that will substantially improve the stability and the overall performance of these optoelectronic devices.