Thesis

Combining 2D Elemental Distributions obtained with Ion Beam Analysis to construct 3D distributions and Applications to perovskite Solar Cells (CEDIBASC)

• Call:

  IDPASC Portugal - PHD Programme 2019

• Academic Year:

  2019 / 2020

• Domain:

  Experimental Particle Physics

• Supervisor:

  Teresa Peña

• Co-Supervisor:

• Institution:

  Instituto Superior Técnico

• Host Institution:

  CTN, DECN and DF -IST

• Abstract:

  Nuclear microprobe and IBA (Ion Beam Analysis) techniques represent a non-destructive and fast tool that can provide elemental 2D compositional maps and elemental depth profiles of samples with a precision up to the micrometric scale. Objective: The objective of this project is to combine 2D elemental distributions given by Particle Induced X-ray Emission (PIXE) with depth resolved Elastic Backscattering Spectrometry (EBS) spectra to obtain 3D elemental distribution information of materials. Method: This will be achieved by means of artificial neural networks and the development of an user-friendly graphical interface which will allow to visualize the 3D structures. Part of the research work will concentrate on the development and training of artificial neural networks (ANN) that promptly analyse and join EBS and PIXE data. Application: This method will be applied to the analysis of the most promising material for solar cells, the perovskites. Implementing also the sensitive Ion Beam Induced Charge (IBIC) technique, a relationship between the perovskites based-solar cells charge collection efficiency and the 3D elemental distributions will be established, contributing to the optimization of cells manufacturing conditions. This relationship is crucial since the composition of the absorber layer is closely related to cell lattice parameter, optical properties and energy band gaps, that finally influence the energy conversion efficiency of the cell. Innovation: The innovative methodological approach of this research project will be to concentrate on a particular material, Perovskite, to develop and properly train ANN algorithms that can calculate elemental 3D distributions of the sample using combined IBA techniques. This will also imply the analysis of samples with the Total-IBA approach, in order to have depth-resolved simulated spectra to use for the ANN training. Collaboration: The project will be done within a collaboration between the Department of Physics of IST and CTN (Centro de Ciências e Tecnologias Nucleares, Luis Cerqueira Alves). CTN has unique conditions in the country for applications of nuclear Physics techniques. In this research work the two facilities to be used are the Van der Graaf accelerator and the nuclear microprobe. They are two important tools to enhance the non-destructive IBA techniques capabilities and results. Possible co-supervision (Celso Franco or Patrícia Gonçalves, for instance) from LIP will also be an added value for the development of software.