An international research team at Kiel University in Germany has developed one of the world's lightest materials-Aerobornitride (air nitride), with a porosity of 99%, almost entirely composed of air. Scientists believe that this can create a basis for introducing lasers into a wider range of applications. The researchers developed a special three-dimensional nanostructure based on boron-nitrogen compounds, which can scatter light in large amounts and hardly absorb light. Under the irradiation of the laser, the material will emit uniform light. Depending on the type of laser, the light emitted by the material is more efficient and powerful than the light emitted by the LED lamp. Therefore, in the future, the material can be used for car headlights, projectors and laser lights used for room lighting can become smaller and brighter.
In research and industrial fields, lasers have always been regarded as the "next generation" light source, and its efficiency can even exceed LEDs (light emitting diodes). Dr. Fabian Schütt said: "If you need to get very bright or a lot of light, you need a lot of LED lights, so you need more space."
The powerful and small size light source can be used in various applications. The first test application is that the material can be used in automotive headlights, but it cannot be used in large-scale laser lights. On the one hand, the laser diode emits strong directional light; on the other hand, the laser lamp has only one wavelength, so it is a monochromatic lamp. Therefore, when the laser beam is irradiated on the surface of the object and is reflected, it will cause flicker and make people uncomfortable.
Professor Rainer Adelung said: "Previous research on laser lamps has usually focused on phosphors, but the light produced by phosphors is relatively cold. In the long run, it is not stable enough and not very efficient." In a different method, a hexagonal boronitride (also called "white graphene") nanostructure was developed, which has a high scattering rate and hardly absorbs light. The structure consists of a network of gold and silver wires composed of countless small hollow microtubes. When the laser beam irradiates the structure, the laser beam is scattered everywhere in the network structure, thereby forming a uniform light source. Schütt explained: "Our materials are a bit like artificial fog, which can produce uniform and pleasant light." The strong scattering rate also means that the human eye will no longer see the flickering light.
This nanostructure not only ensures that the material can withstand intense laser light, but also can scatter light of different wavelengths. In addition to white lasers, red, green, and blue lasers can be mixed to produce specific color effects, for example, for creative room lighting. Therefore, in the future, a very light-weight laser diode may produce a completely new design concept. However, in order to be able to compete with future LEDs, the efficiency of laser diodes must also be improved. The research team is currently looking for industrial partners to move the material from the laboratory to practical applications.
At the same time, in addition to boron nitride and graphene or graphite, researchers at Keele University are still using its method to develop porous nanostructures suitable for different materials. In this way, more and more new and lightweight materials can be created to achieve innovative applications. For example, scientists at Keele University are currently working with companies and other universities to develop self-cleaning air filters for aircraft.