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Research led by scientists at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) and the Energy Frontier Research Center’s (EFRC) Hybrid Organic and Inorganic Semiconductor Center for Energy (CHOISE) induces chirality in halide perovskites. A new process has been discovered. Semiconductors can open the door to cutting-edge electronic applications.
This diagram shows how the structure of a halide perovskite is distorted when it interacts with chiral molecules. Image from CHOISE
This development is the latest in a series of advances by the team in introducing and controlling chirality. Chirality refers to structures that cannot be superimposed into mirror images, such as hands, and allows for greater control over electrons by directing their “spin.” Most conventional optoelectronic devices in use today rely on control of charge and light, but not electron spin.
The researchers successfully created spin-polarized LEDs using chiral perovskite semiconductors at extremely low temperatures and in the absence of a magnetic field, as previously reported. The latest advances accelerate the materials development process for spin control.
The details are detailed in a newly published paper, “Remote chirality transitions in low-dimensional hybrid metal halide semiconductors,” published in the journal Nature Chemistry. The key was to introduce chiral molecules with different head groups into the perovskite. Chiral molecules intentionally do not fit into the perovskite lattice, “twisting” the structure away from the surface. Chiral molecules transmit their properties deep into the perovskite structure in several unit cells or layers. This twist can be controlled by introducing left-handed or right-handed chiral molecules at the grain boundaries and surfaces of perovskite films, and the spin properties are controlled accordingly. Such twisted structures enable unique capabilities for energy applications, with spin control adding further possibilities by acting as an electronic spin filter.
Md Azimul Haque, lead author of the paper, said that introducing chirality into low-dimensional perovskite semiconductors typically involves chiral molecules existing within the perovskite lattice, so each time the composition of the chiral molecules is changed, a wide range of He said an analysis would be required. The proximal chiral molecule can transfer its properties without changing the perovskite composition, making the process simpler and faster, and with fewer constraints on composition, he said.
“Compared to traditional methods, we can now create materials with known properties with added chirality very easily,” said postdoctoral researcher Haque. “The next step is to experiment with the material and incorporate it into new applications.”
Funding for this research is provided by the Department of Energy’s Office of Science’s EFRC program. This research relied on extensive expertise from CHOISE, including NREL, the University of Utah, the University of Colorado Boulder, the University of Wisconsin-Madison, and Duke University.
Hybrid perovskites refer to crystalline structures containing both inorganic and organic components. In other semiconductors, such as those made from silicon, the material is purely inorganic and hard. Because hybrid perovskites are softer and more flexible, “the twisting of molecules on the surface therefore affects deeper into this semiconductor than in most hard inorganic semiconductors,” said Joey Luther, NREL senior scientist and corresponding author. he said.
Co-authors from NREL are Steven Harvey, Roman Brunecky, Jiselle Ye, Bennett Addison, Yifan Dong, Matthew Hautzinger, Kai Zhu, Jeffrey Blackburn, Joseph Berry, and Matt Beard. Other CHOISE co-authors include Andrew Grieder, Yuan Ping, Junxiang Zhang, Seth R. Marder, Heshan Hewa Walpitage, Zeev Valy Vardeny, Yi Xie, and David B. Mitzi.
“This is a new way to induce chirality in halide perovskites,” Luther said. “And it could lead to technologies that we can’t really imagine, but it could be polarized cameras, 3D displays, spin information transfer, something closer to optical technology,” he says, “and it could lead to technologies that we can’t really imagine, but it could be something closer to optical technology, such as polarized cameras, 3D displays, spin information transfer, optical computing, or better optical computing.” Communication, things of that nature. ”
