New technique paves the way for perfect perovskites
Next-gen solar material could outshine other solar cells

Date:
October 19, 2021
Source:
DOE/Lawrence Berkeley National Laboratory
Summary:
Scientists have developed a new technique that allows researchers
to synthesize a perovskite solar material, characterize its crystal
structure, and test its response to light at the same time.



FULL STORY ==========================================================================
An exciting new solar material called organic-inorganic halide perovskites could one day help the U.S. achieve its solar ambitions and decarbonize
the power grid. One thousand times thinner than silicon, perovskite
solar materials can be tuned to respond to different colors of the solar spectrum simply by altering their composition mix.


========================================================================== Typically fabricated from organic molecules such as methylammonium
and inorganic metal halides such as lead iodide, hybrid perovskite
solar materials have a high tolerance for defects in their molecular
structure and absorb visible light more efficiently than silicon, the
solar industry's standard.

Altogether, these qualities make perovskites promising active layers not
only in photovoltaics (technologies that convert light into electricity),
but also in other types of electronic devices that respond to or control
light including light-emitting diodes (LEDs), detectors, and lasers.

"Although perovskites offer great potential for greatly expanding solar
power, they have yet to be commercialized because their reliable synthesis
and long- term stability has long challenged scientists," said Carolin Sutter-Fella, a scientist at the Molecular Foundry, a nanoscience user
facility at Lawrence Berkeley National Laboratory (Berkeley Lab). "Now,
a path to perfect perovskites may soon be within reach." A recent Nature Communications study co-led by Sutter-Fella reports that solar materials manufacturing could be aided by a sophisticated new instrument that uses
two types of light -- invisible X-ray light and visible laser light --
to probe a perovskite material's crystal structure and optical properties
as it is synthesized.

"When people make solar thin films, they typically have a dedicated
synthesis lab and need to go to another lab to characterize it. With
our development, you can fully synthesize and characterize a material
at the same time, at the same place," she said.



==========================================================================
For this work, Sutter-Fella assembled an international team of top
scientists and engineers to equip an X-ray beamline endstation with a
laser at Berkeley Lab's Advanced Light Source (ALS).

The new instrument's highly intense X-ray light allows researchers to
probe the perovskite material's crystal structure and unveil details about
fast chemical processes. For example, it can be used to characterize
what happens in the second before and after a drop of a solidifying
agent transforms a liquid precursor solution into a solid thin film.

At the same time, its laser can be used to create electrons and holes (electrical charge carriers) in the perovskite thin film, allowing the scientists to observe a solar material's response to light, whether as a finished product or during the intermediate stages of material synthesis.

"Equipping an X-ray beamline endstation with a laser empowers users
to probe these complementary properties simultaneously," explained Sutter-Fella.

This combination of simultaneous measurements could become part of an
automated workflow to monitor the production of perovskites and other functional materials in real time for process and quality control.



========================================================================== Perovskite films are typically made by spin coating, an affordable
technique that doesn't require expensive equipment or complicated
chemical setups. And the case for perovskites gets even brighter when you consider how energy- intensive it is just to manufacture silicon into a
solar device -- silicon requires a processing temperature of about 2,732 degrees Fahrenheit. In contrast, perovskites are easily processed from
solution at room temperature to just 302 degrees Fahrenheit.

The beamline endstation allows researchers to observe what happens during synthesis, and in particular during the first few seconds of spin coating,
a critical time window during which the precursor solution slowly begins
to solidify into a thin film.

First author Shambhavi Pratap, who specializes in the use of X-rays
to study thin-film solar energy materials, played a critical role
in developing the instrument as an ALS doctoral fellow. She recently
completed her doctoral studies in the Mu"ller-Buschbaum group at the
Technical University of Munich.

"The instrument will allow researchers to document how small things that
are usually taken for granted can have a big impact on material quality
and performance," Pratap said.

"To make reproducible and efficient solar cells at low cost, everything matters," Sutter-Fella said. She added that the study was a team effort
that spanned a wide range of scientific disciplines.

The work is the latest chapter in a body of work for which Sutter-Fella
was awarded a Berkeley Lab Early Career Laboratory Directed Research
and Development (LDRD) Award in 2017.

"We know that the research community is interested in using this
new capability at the ALS," she said. "Now we want to make it user
friendly so that more people can take advantage of this endstation." ========================================================================== Story Source: Materials provided by
DOE/Lawrence_Berkeley_National_Laboratory. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Shambhavi Pratap, Finn Babbe, Nicola S. Barchi, Zhenghao Yuan, Tina
Luong, Zach Haber, Tze-Bin Song, Jonathan L. Slack, Camelia
V. Stan, Nobumichi Tamura, Carolin M. Sutter-Fella, Peter
Mu"ller-Buschbaum. Out- of-equilibrium processes in crystallization
of organic-inorganic perovskites during spin coating. Nature
Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-25898-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211019110527.htm

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