Researchers at the University of California, Davis recently found that perovskites may enable a new class of light-responsive semiconductor devices. They discovered that halide perovskite crystals can reversibly change shape when exposed to light. This reversible photostriction effect could open the door to new semiconductor applications previously not feasible.
After establishing the light-responsive potential of perovskite crystals, the team illuminated them with laser light and monitored changes in their atomic structure using an X-ray probe. The crystals were synthesized by collaborators Bekir Turedi, Andrii Kanak, and Professor Maksym Kovalenko at ETH Zürich, Switzerland. Support came from the Defense Advanced Research Projects Agency program for developing new materials for switchable photonic devices and from the National Science Foundation. The experiments revealed that exposure to light induces a rapid and fully reversible shift in the crystal lattice.
While the findings highlight the unique light-responsive behavior of perovskites, these materials are classified as semiconductors, yet they exhibit distinct behaviors compared to conventional materials such as silicon and gallium arsenide. They can incorporate both organic and inorganic components and are often more cost-effective to produce. All perovskites share a fundamental ABX3 crystal structure, a configuration in which a central atom is surrounded by six others in an octahedral arrangement, all enclosed within a cubic lattice with atoms at each corner.
“They are ‘smart materials’ that can be tuned to respond to a stimulus in a way we can control,” said Marina Leite, professor of materials science and engineering at UC Davis and senior author on the paper. “Their chemistry is very different in a way that can be beneficial for creating devices we couldn’t build before.” This photostriction effect can be repeated many times without degrading the material.
Researchers can further modulate how perovskites interact with light by altering their composition, changing the bandgap that defines the range of light wavelengths the material absorbs and emits. Different formulations show varying degrees of structural response when exposed to light above this bandgap. Researchers can precisely control the effect by adjusting both the frequency and intensity of the incident light. They can scale the response, causing it to behave like a dimmer, depending on the type and intensity of light shining on the crystals.
Leite emphasized that this light-driven structural response marks a key innovation, enabling new devices that switch or tune in response to light. These materials enable the development of new electronic devices, such as sensors and actuators, for use in optoelectronics and next-generation solar cells, underscoring the study's broad impact.
