Light energy is found everywhere and harnessed for various applications, such as night vision technology, solar cells, biomedical imaging, and sensors. Converting low-energy light to high-energy light is crucial in many of these technologies. 

Some of the existing methodologies include the use of upconversion materials which infrared light to visible or ultraviolet light, quantum dots which absorb low-energy photons and re-emit them as higher-energy photons, frequency doubling crystals that double the frequency of light, and photovoltaic (or solar) cells which convert sunlight into electricity.

Now, scientists have added a new technology to this list: a new class of material that transforms low-energy light into high-energy light.  

The research team included scientists from the University of Texas at Austin, the University of California Riverside, the University of Colorado Boulder, and the University of Utah, who have been working on developing this technology for several years.

Organic-inorganic composite material

The team developed a composite material using inorganic and organic materials. For the inorganic material, the team used ultra-small silicon nanoparticles and anthracene for the organic material.

Anthracene has unique properties in fossil fuels such as petroleum and coal. It is fluorescent, meaning it can absorb light at specific wavelengths and re-emit light at longer wavelengths, making it a suitable candidate for this technology.  

The team developed electrically conductive bridges to transport the electrons between the organic anthracene and inorganic silicon nanoparticles. The composite efficiently transports the electrons between the organic and inorganic components, with the bridge facilitating the process by ensuring a strong chemical bond between the two parts and increasing the energy exchange efficiency. 

New composite material converts low-energy light to high-energy light. Image: University of Texas/Austin

The material can convert long-wavelength photons (such as red light) into short-wavelength blue or ultraviolet photons, enabling applications. A longer wavelength implies lower energy in physics, meaning the material can convert low-energy light into high-energy light.

Future applications in technologies

The novel organic-inorganic composite material opens up new possibilities in many fields, such as biomedical imaging, light sensors for self-driving cars, efficient solar panels, better night vision goggles, and light-based 3D printing.

Sean Roberts, the co-author of the study from the University of Texas at Austin, says: “This process gives us a whole new way of designing materials. It allows us to take two extremely different substances, silicon and organic molecules, and bond them strongly enough to create not just a mixture, but an entirely new hybrid material with properties that are completely distinct from each of the two components.

“This concept may be able to create systems that can see in near-infrared. That can be useful for autonomous vehicles, sensors, and night vision systems.”

Most importantly, the ability to transform low-energy light into higher-energy light has the potential to enhance the efficiency of solar cells by capturing near-infrared light that would otherwise pass through. Optimising this technology could lead to a 30% reduction in the size of solar panels. 

The findings of the study are published in the journal Nature Chemistry.