SCL Online Seminar by Nenad Vukmirović

Thursday, 09 December 2021

You are cordially invited to the SCL online seminar of the Center for the Study of Complex Systems, which will be held on Thursday, 9 December 2021 at 14:00 on Zoom. The talk entitled

Charge pair transport pathway in organic solar cells

will be given by Dr. Nenad Vukmirović (Scientific Computing Laboratory, Center for the Study of Complex Systems, Institute of Physics Belgrade). Abstract of the talk:

Solar cells based on organic semiconductors have been widely investigated in the last three decades with a continuous improvement in their performance and lifetime and improved understanding of the processes that take place in the device. The first part of the talk will consist of a brief review of this research field and a review of our previous efforts aimed at understanding the key process in the solar cell - the separation of photo-generated charge pairs (excitons). Our recent results will be presented in the second part of the talk [1, 2]. We model the system using a microscopic effective Hamiltonian that takes into account the most relevant processes that determine the dynamics of excitons. The results for energy and time resolved dynamics of charge pairs from the moment of their photogeneration to the moment of their extraction or recombination will be presented. The results indicated that charge separation proceeds via the cold pathway in which donor excitons convert to relaxed charge-transfer excitons which further transform to the states of separated charges [1]. We further analyze these results from the perspective of non-equilibrium thermodynamics. We determine the difference between equilibrium and non-equilibrium dependence of free energy on charge pair separation distance. Our results indicated that this difference is largest when charge separation efficiency is large which led us to conclude that charge separation in efficient organic solar cells proceeds via a cold but nonequilibrated pathway [2].

[1] V. Janković and N. Vukmirović, J. Phys. Chem. C 124, 4378 (2020).
[2] W. Kaiser, V. Janković, N. Vukmirović, and A. Gagliardi, J. Phys. Chem. Lett. 12, 6389 (2021).

  • Screen Shot 2021-12-09 at 13.59.26
  • Screen Shot 2021-12-09 at 13.59.45
  • Screen Shot 2021-12-09 at 14.05.02
  • Screen Shot 2021-12-09 at 14.07.06
  • Screen Shot 2021-12-09 at 14.10.23
  • Screen Shot 2021-12-09 at 14.13.02
  • Screen Shot 2021-12-09 at 14.17.43
  • Screen Shot 2021-12-09 at 14.17.54
  • Screen Shot 2021-12-09 at 14.20.05
  • Screen Shot 2021-12-09 at 14.23.48
  • Screen Shot 2021-12-09 at 14.25.14
  • Screen Shot 2021-12-09 at 14.27.54
  • Screen Shot 2021-12-09 at 14.32.08
  • Screen Shot 2021-12-09 at 14.37.38
  • Screen Shot 2021-12-09 at 14.39.04
  • Screen Shot 2021-12-09 at 14.42.36
  • Screen Shot 2021-12-09 at 14.47.12
  • Screen Shot 2021-12-09 at 14.49.34
  • Screen Shot 2021-12-09 at 14.50.47
  • Screen Shot 2021-12-09 at 14.56.47