<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class="" style="font-family: HelveticaNeue;"><span class="">Dear Colleagues,</span></div><div class="" style="font-family: HelveticaNeue;"><span class=""><br class=""></span></div><div class="" style="font-family: HelveticaNeue;"><span class="">We would like to draw your attention to a seminar of a guest of the Faculty of Physics at UW. </span>On Monday 15 May 2023 at 9:30 AM at the UW Faculty of Physics (Pasteura 5, Warsaw; room B0.14) we are hosting a seminar during which</div><div class=""><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal; min-height: 14px;"><font face="HelveticaNeue" class=""><br class=""></font></div><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue" class=""><b class="">Tony Ladd </b>(University of Florida)</font></div><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal; min-height: 14px;"><font face="HelveticaNeue" class=""><br class=""></font></div><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue" class="">will give a talk</font></div><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal; min-height: 14px;"><font face="HelveticaNeue" class=""><br class=""></font></div><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue" class=""><b class="">Bayesian Monte-Carlo for photovoltaic materials characterization</b></font></div><div style="font-family: HelveticaNeue;" class=""><br class=""></div></div></div></div><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal;"><b class="">Abstract</b></div><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal;">Quantifying rates of charge carrier recombination is an important
step in developing solar cells with high power conversion
efficiencies (PCE). However, recovering characteristic parameters
such as carrier mobility, dopant concentration, and recombination
rate constants is hindered by the interplay between carrier dynamics
and the various recombination mechanisms. Interpretation of
optoelectronic measurements, such as time-resolved photoluminescence
(TRPL), usually relies on analytically tractable simplifications of
the underlying physics models for carrier mobility and recombination,
which can sacrifice much of the information content of the
measurement.</div><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal;">Bayesian inference
is a means of efficiently solving inverse problems. Rather than
trying to locate a single optimum solution, it creates a probability
distribution in the parameter space, based on the differences between
simulated and measured data. In this case the forward problem is
straightforward – given a set of material parameters, what does the
TRPL curve look like. The inverse problem is to determine the
material parameters from a given set of experimental data. I will
present results to show that a small number of TRPL scans are
sufficient to determine accurate values for most of the key
optoelectronic parameters: carrier mobility, doping level, Auger and
radiative recombination rates, and the bulk and surface contributions
to the non-radiative decay. Minimizing non-radiative decay is a key
to designing solar cells with high PCE.</div><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal;">Bayesian inference
is quite computationally expensive, requiring a numerical solution of
the classical drift-diffusion equations (in 1D) for each parameter
set. To reduce the computational demands to manageable proportions,
we have implemented a Metropolis Monte Carlo sampling, which can
efficiently locate and sample the high probability region of the
distribution.</div><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal;"><div class="" style="margin: 0cm; background-color: white;"><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><br class=""></div></div></div><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal;">We warmly welcome everyone to attend the talk. Please note that, since it is outside of the Soft Matter and Complex Systems seminar schedule, attendance is not compulsory (although warmly encouraged!) for students taking the seminar.</div><div class="" style="font-family: HelveticaNeue; margin: 0px; font-stretch: normal; line-height: normal;"><br class=""></div></div><div class="" style="font-family: HelveticaNeue;"><div dir="auto" class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div class=""><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue" class="">Maria Ekiel-Jeżewska</font></div><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue" class="">Maciej Lisicki</font></div><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue" class="">Piotr Szymczak</font></div><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue" class="">Panagiotis Theodorakis</font></div><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><font face="HelveticaNeue" class="">Marek Trippenbach</font></div></div></div></div></div><div class=""><div dir="auto" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class=""><br class=""></div></div><br class="Apple-interchange-newline"><br class="Apple-interchange-newline">
</div>
<br class=""></body></html>