Optoelectronics Gain Spin Control From Chiral Perovskites and III-V Semiconductors
2024年7月2日 - 2:03AM
A research effort led by scientists at the U.S. Department of
Energy’s (DOE’s) National Renewable Energy Laboratory (NREL) has
made advances that could enable a broader range of currently
unimagined optoelectronic devices.
The researchers, whose previous innovation
included incorporating a perovskite layer that allowed
the creation of a new type of polarized light-emitting diode (LED)
that emits spin-controlled photons at room temperature without the
use of magnetic fields or ferromagnetic contacts, now have gone a
step further by integrating a III-V semiconductor optoelectronic
structure with a chiral halide perovskite semiconductor. That is,
they transformed an existing commercialized LED into one that also
controls the spin of electrons. The results provide a pathway
toward transforming modern optoelectronics, a field that relies on
the control of light and encompasses LEDs, solar cells, and
telecommunications lasers, among other devices.
“It's up to one's imagination where this might go or where this
might end up,” said Matthew Beard, a senior research fellow at NREL
and coauthor of the newly published Nature article, “Room
temperature spin injection across a chiral-perovskite/III-V
interface.”
Beard also serves as director of the Center for Hybrid Organic
Inorganic Semiconductors for Energy (CHOISE), an Energy Frontier
Research Center funded by the Office of Science Basic Energy
Sciences within DOE. The reported research was funded by CHOISE and
relied on a broad range of scientific expertise drawn from NREL,
the Colorado School of Mines, University of Utah, University of
Colorado Boulder, and the Universite de Lorraine in France.
The goal of CHOISE is to understand control over the
interconversion of charge, spin, and light using carefully designed
chemical systems. In particular, the work focuses on control over
the electron spin that can be either “up” or “down.” Most
current-day optoelectronic devices rely on the interconversion
between charge and light. However, spin is another property of
electrons, and control over the spin could enable a wide plethora
of new effects and functionality. The researchers published a paper
in 2021 in which they reported how by using two different
perovskite layers they were able to control the spin by creating a
filter that blocks electrons “spinning” in the wrong direction.
They hypothesized at the time that advancements could be made in
optoelectronics if they could successfully incorporate the two
semiconductors, and then went on to do just that. The breakthroughs
made, which include eliminating the need for subzero Celsius
temperatures, can be used to increase data processing speeds and
decrease the amount of power needed.
“Most current-day technologies are all based on controlling
charge,” Beard said. “Most people just forget about the electron
spin, but spin is very important, and it's also another parameter
that one can control and utilize.”
Manipulating the spin of electrons in a semiconductor has
previously required the use of ferromagnetic contacts under an
applied magnetic field. Using chiral perovskites, the researchers
were able to transform an LED to one that emits polarized light at
room temperature and without a magnetic field. Chirality refers to
the material's structure that cannot be superimposed on its mirror
image, such as a hand. For example, a “left-handed” oriented chiral
system may allow transport of electrons with “up” spins but block
electrons with “down” spins, and vice versa. The spin of the
electron is then converted to the “spin,” or polarization, of the
emitted light. The degree of polarization, which measures the
intensity of light that is polarized in one direction, reached
about 2.6% in the previous research. The addition of the III-V
semiconductor—which is made of materials in the third and fifth
columns of the periodic table—boosted the polarization to about
15%. The degree of polarization serves as a direct measure of spin
accumulation in the LED.
“This work is particularly exciting to me, as it combines spin
functionality with a traditional LED platform,” said the first
author of the work, Matthew Hautzinger. “You can buy an LED
analogous to what we used for 14 cents, but with the chiral
perovskite incorporated, we’ve transformed an already robust (and
well understood) technology into a futuristic spin-control
device.”
Other NREL researchers listed as coauthors are Steven Hayden,
Jiselle Ye, Qi Jiang, Mickey Wilson, Alan Phillips, Yifan Dong,
Emily Raulerson, Ian Leahy, Chun-Sheng Jiang, Jeffrey Blackburn,
Joseph Luther, Katherine Jungjohann, Joseph Berry, and Kirstin
Alberi.
NREL is the U.S. Department of Energy's primary national
laboratory for renewable energy and energy efficiency research and
development. NREL is operated for DOE by the Alliance for
Sustainable Energy LLC.
Wayne Hicks
National Renewable Energy Laboratory
303-275-4051
Wayne.Hicks@nrel.gov