Title: Unified thermodynamic theory for light-induced phase separation in mixed halide perovskites

Speaker: Zehua Chen (TU/e, Computational Materials Physics Group)
Time: Oct. 29, 2020, 10:00–11:00
Location: Online (MS Teams)

Abstract | Under illumination, mixed halide perovskites that are thermodynamically stable in the dark can demix due to a free energy lowering of photocarriers that funnel to a nucleated phase with different halide composition and lower band gap than the parent phase. This is problematic for applying mixed halide perovskites in solar cells. I will present in this seminar a unified thermodynamic theory for this light-induced phase separation and apply it to five mixed iodine-bromine perovskites. The spinodals separating metastable and unstable regions in the composition-temperature phase diagrams shift upward in temperature under illumination, while new light-induced binodals separating stable and metastable regions appear that signal nucleation of a low-band gap iodine-rich phase. The threshold photocarrier density for phase separation is mainly governed by the band gap difference of the parent and iodine-rich phase. Partial replacement of organic cations by cesium reduces this difference and therefore has a stabilizing effect.

The CCER seminars are aimed at researchers interested in computational approaches to (energy) research. The seminar is small-scale, typically 15 participants, and interactive, offering lots of room for discussion. If you would like to attend, just This email address is being protected from spambots. You need JavaScript enabled to view it. so as to receive the MS Teams meeting link.

Title: Study and Design of Multifunctional Nanostructured Materials and complex molecules for Energy Applications

Speaker: Sofía Calero (TU/e, MSM)
Time: Oct. 8, 2020, 10:00–11:00
Location: Online (MS Teams)

On Sept. 1, we launched the Materials Simulation and Modelling Group (MSM) in the Department of Applied Physics. This group provides conceptual knowledge with the goal of achieving reductions in energy consumption and paving the way to develop a long-term research strategy to design and ‘invent’ materials. The group's research has three main branches: (1) Density Functional Theory based multiscale computer simulations with main focus on perovskite solar cells, (2) electronic structure 2D materials and (3) molecular simulations of porous materials and complex molecules. This presentation will focus on the latter branch, discussing the state of the art, current work, and what we envision in the short and long term. In particular, I will discuss force field development and high-performance methods for automatically calculating surface properties, as well as innovative approaches to assessing material stability and for identifying and designing high-performance multi-functional nanostructured materials.

The CCER seminars are aimed at researchers interested in computational approaches to (energy) research. The seminar is small-scale, typically 15 participants, and interactive, offering lots of room for discussion. If you would like to attend, just This email address is being protected from spambots. You need JavaScript enabled to view it. so as to receive the MS Teams meeting link.

 

Title: To be determined

Speaker: Guido Lange, Yesh Melese (TU/e, Fusion)
Time: June 11, 2020, 10:00–11:00
Location: Differ, Alexander-zaal

The CCER seminars are aimed at researchers interested in computational approaches to (energy) research. The seminar is small-scale, typically 15 participants, and interactive, offering lots of room for discussion. If you don't have access to the DIFFER building but would like to attend, just This email address is being protected from spambots. You need JavaScript enabled to view it..

Title: Computer simulations of co-crystalline electrolytes for all-solid alkali metal batteries

Speaker: Arun Venkatnathan (IISER, Pune, India)
Time: May 28, 2020, 10:00–11:00
Location: Online (MS Teams)

Dr. Arun Venkatnathan is an Associate Professor in Chemistry at the Department of Chemistry and the Centre for Energy Science at IISER, the Indian Institute of Science Education and Research in Pune, India. Dr. A. Venkatnathan group's webpage may be found at: http://www.iiserpune.ac.in/~arun/

Abstract | Soft-solid co-crystalline electrolytes for lithium/sodium ion batteries exhibit excellent thermal stability and high ionic conductivity. These electrolytes are matrices of organic solvents (e.g. DMF, adiponitrile) coordinated with cations (Li+/Na+), where counter anions occupies the remaining space in crystals. In this talk, I will present a molecular understanding of structure, thermal stability and ion transport in some electrolytes from Molecular Dynamics simulations. The simulations mimic the processes of decomposition/melting of electrolytes and show a liquid-like surface layer on the nano-sized grains of these electrolytes as seen from several experiments performed by colloborators. The simulations also examine the dynamics of ions on the surface and bulk. The insights from simulations combined with experiments is expected to lead to the development of better and safer electrolytes for batteries.

P. Prakash, J. Aguirre, M. Van Vliet, P. Chinnam, D. Dikin, M. Zdilla, S. Wunder, A. Venkatnathan, Unravelling the structural and dynamical complexity of the equilibrium liquid grain-binding layer in highly conductive organic crystalline electrolytes, J. Mat. Chem. A, 6, 4394 (2018).

B. Fall, P. Prakash, M. R. Gau, S. L. Wunder, A. Venkatnathan and M. J. Zdilla, Experimental and theoretical investigation of the ion conduction mechanism of tris(adiponitrile)perchloratosodium, a self-binding, melt-castable crystalline sodium electrolyte, Chemistry of Materials, 31, 8850 (2019).

Seminar | The CCER seminars are aimed at researchers interested in computational approaches to (energy) research. The seminar is small-scale, typically 15 participants, and interactive, offering lots of room for discussion. If you would like to attend, just This email address is being protected from spambots. You need JavaScript enabled to view it. so as to receive the MS Teams meeting link.