A single-crystal organometallic perovskite optical fiber. Image: Dr Lei Su.
A single-crystal organometallic perovskite optical fiber. Image: Dr Lei Su.

Due to their very high efficiency at generating electricity from light, perovskites are predicted to be the next-generation material for solar panels and LED displays. A team led by Lei Su at Queen Mary University of London in the UK has now shown that they could also become the next-generation material for optical fibers. The team reports its findings in a paper in Science Advances.

Optical fibers are tiny wires as thin as a human hair, in which light travels at a superfast speed – 100 times faster than electrons in cables. These tiny optical fibers transmit the majority of our internet data. At present, most optical fibers are made of glass.

The perovskite optical fiber made by Su’s team consists of just one piece of a perovskite crystal. These optical fibers have a core width as low as 50μm (the size of a human hair) and are very flexible.

Compared to their polycrystal counterparts, single-crystal organometallic perovskites are more stable, more efficient, more durable and have fewer defects. Scientists have therefore been seeking to make single-crystal perovskite optical fibers that can bring this high efficiency to fiber optics. 

“Single-crystal perovskite fibers could be integrated into current fiber-optical networks, to substitute key components in this system – for example in more efficient lasing and energy conversions, improving the speed and quality of our broadband networks,” said Su, a reader in photonics at Queen Mary University of London.

Using a new and inexpensive temperature-growth method, Su's team was able to grow single-crystal organometallic perovskite fibers in a liquid solution, and precisely control their length and diameter. They gradually changed the heating position, line contact and temperature during this process to ensure continuous growth in the length of the optical fiber while preventing random growth in its width. With their method, the length of the fiber can be controlled, and the cross section of the perovskite fiber core can be varied.

In line with their predictions, due to the single-crystal quality, their fibers proved to have good stability over several months, and a small transmission loss – lower than 0.7dB/cm – which is sufficient for making optical devices. The fibers also have great flexibility – they can be bent to a radius as small as 3.5mm – and larger photocurrent values than those of a polycrystalline counterpart.

“This technology could also be used in medical imaging as high-resolution detectors,” Su said. “The small diameter of the fiber can be used to capture a much smaller pixel compared to the state of the art. So that means by using our fiber we can have the pixel in micrometer scales, giving a much, much higher resolution image for doctors to make better and more accurate diagnosis. We could also use these fibers in textiles that absorb the light. Then when we're wearing, for example, clothes or a device with these kinds of fiber woven into the textile, they could convert solar energy into electrical power. So we could have solar-powered clothing.”

This story is adapted from material from Queen Mary University of London, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.