2020 Annual Meeting of the Far West Section
Volume 65, Number 17
Friday–Saturday, October 9–10, 2020;
Virtual, Pacific Time
Session G01: Condenser Matter Physics
11:00 AM–11:45 AM,
Saturday, October 10, 2020
Chair: Alex Frano, University of California, San Diego
Abstract: G01.00001 : Characterization of Surfaces and Interfaces in Solar Devices - Magic Treatments, Alternative Materials, and What They Do to the Electronic Structure
11:00 AM–11:45 AM
Preview Abstract
Author:
Clemens Heske
(University of Nevada Las Vegas (UNLV) and Karlsruhe Institute of Technology (KIT))
Thin-film photovoltaic (PV) cells have reached conversion efficiencies well
above 20{\%}, just like high-quality silicon devices. At first glance, then,
one would think that ``we are done''. However, the opposite is true: the
real challenges of renewable energy conversion lie ahead, in particular when
``magic'' treatments or ``alternative'' materials are to be employed. Even
more so, solar water splitting (``Photoelectrochemistry'' or ``PEC'') is
just at the beginning of its development towards a viable energy technology
of the future. Making it all happen will require a detailed understanding of
the electronic and chemical properties of materials and interfaces, and
that's where high-end characterization approaches come into play.
Using a tool chest of electron and soft x-ray spectroscopic methods, it is
possible to unravel (some of) the secrets of candidate materials and their
interfaces. Our tool chest includes lab-based photoelectron and Auger
electron spectroscopy (in Las Vegas), and soft x-ray emission and absorption
spectroscopy using high-brilliance synchrotron radiation (in Berkeley).
While the electron-based techniques are very surface-sensitive, the two
synchrotron methods are photon-in-photon-out techniques that probe the bulk
region near the surface.
Using Cu(In,Ga)(S,Se)$_{\mathrm{2}}$ (CIGSSe) as an efficient model material
for PV and PEC devices alike, the talk will present experiments that gain
insights into surface treatments, alternative materials, and their
interfaces, in particular in view of the chemical and electronic structure,
and, ultimately, the device performance (and stability, and cost, and
\textellipsis ). And while the main focus will be on specific solar
materials, attempts will be made to convince the esteemed listeners that
these characterization techniques can be applied to a wide variety of
different materials and their surfaces/interfaces, regardless of
application.