Title: Modeling novel thermal transport phenomena in semiconductor nanowires.

Speaker: Subash Gireesan (CCER)
Time: March 11, 2021, 10:00–11:00
Location: Online (MS Teams)

Abstract: Transport of heat, i.e. thermal energy, plays an important role in our daily lives. Ranging from regulating the temperature of our body to cooling down our electronic devices, the importance of heat transport is not often valued as we go about with our lives. Efficient management of heat is crucial in designing devices like internal combustion engines, electronics, space crafts, solar collectors, gas turbines and radiators. In some applications, excess heat has to be removed and in others, it has to be added. The challenge for the engineers and scientists is to design systems in such a way that the usage or dissipation of heat can be optimized. In the last few decades, manipulating and controlling thermal transport at the nanoscale has garnered wide interest. This is mainly motivated by the need for understanding and improving the efficiency of systems and devices for various technological applications like thermal management of microelectronics, thermoelectric energy conversion, thermal energy storage and thermal rectification. Probing thermal transport in nanoscale materials like semiconductor nanowires has revealed novel transport behavior like room-temperature ballistic transport of phonons. For a better understanding of the origin of novel thermal transport phenomena in nanomaterials, new models and theories are required. In this talk, I will present some of the main results from our work on modeling thermal transport in semiconductor nanowires. I will briefly talk about the models that we developed to better understand novel results from thermal transport measurements on GaP nanowires.

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: Artificial Intelligence-aided Discovery of 2D Materials

Speaker: Murat Sorkun (DIFFER, Autonomous Energy Materials Discovery group)
Time: Jan. 14, 2021, 10:00–11:00
Location: Online (MS Teams)

Murat will discuss the recent Nature publication he wrote together with Séverin Astruc, Vianney Koelman and Süleyman Er. Link: https://www.nature.com/articles/s41524-020-00375-7

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: Towards efficient organic thermoelectrics: the interplay between theory and experiment.

Speaker: Jan Anton Koster (University of Groningen)
Time: Dec. 17, 20201, 10:00–11:00
Location: Online (MS Teams)

Koster’s research group is part of the Photophysics and Optoelectronics research unit at the Zernike Institute for Advanced Materials, University of Groningen. The group studies the physics of novel semiconductors and devices. The group’s website may be found at https://www.rug.nl/research/zernike/photophysics-and-opto-electronics/koster-group/

The group is also the driving force behind SIMsalabim: A 1D drift-diffusion simulator for semiconductor devices (LEDs, solar cells, diodes, organics, perovskites). SIMsalabim can be used to simulate current-voltage (JV) characteristics of semiconductor devices. It includes the effects of generation, recombination and trapping of electrons and holes, the effect of ions and dopants, and self-consistently solves the electric field that results from all charged species. More on this may be found at the group’s GitHub page: https://github.com/kostergroup/SIMsalabim

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: 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.