Scientists have discovered that a special type of material called perovskite can physically change shape when exposed to light.
This surprising behavior could lead to new kinds of electronic devices that respond directly to light instead of electricity.
The research, led by a team at the University of California, Davis, was published in the journal Advanced Materials.
Perovskites are a class of materials that act as semiconductors, meaning they can conduct electricity under certain conditions.
Unlike traditional semiconductors such as silicon, perovskites have a flexible chemical structure that can include both organic and inorganic components.
This makes them easier and cheaper to produce, while also allowing scientists to tailor their properties for different uses.
What makes this discovery exciting is how these materials respond to light. When researchers shone a laser onto perovskite crystals, they observed that the internal structure of the material—known as the crystal lattice—changed almost instantly. Even more importantly, the change was reversible. Once the light was removed, the material returned to its original form.
This effect, known as photostriction, is not seen in conventional semiconductor materials. It means that light alone can cause a physical transformation in the material without the need for mechanical force or electrical input.
To understand what was happening, the team used X-ray techniques to observe the crystal structure in real time as it reacted to light. The crystals themselves were carefully grown by collaborators at ETH Zürich in Switzerland. The results showed that the lattice structure could shift repeatedly without damage, making the process stable and reliable.
Another key feature of perovskites is that their response to light can be adjusted. By changing the chemical composition of the material, scientists can control which wavelengths of light the crystal absorbs. This property, known as the bandgap, determines how the material interacts with light.
The researchers found that the degree of structural change depends on both the color and intensity of the light. Instead of acting like a simple on-and-off switch, the material can respond gradually, more like a dimmer that adjusts based on how much light is applied.
This tunable behavior opens up many possibilities for future technologies. Devices could be designed to change shape, switch states, or perform actions simply by being exposed to light. Potential applications include light-controlled sensors, tiny mechanical systems, or advanced optical devices.
Overall, the study highlights how perovskites are not just useful for solar cells and electronics, but also as “smart materials” that actively respond to their environment. As research continues, these light-sensitive crystals could play a key role in the next generation of innovative technologies.
Source: UC Davis.
