What happens if femtosecond laser light is shone on tellurite glass? In her thesis work, Gözden Torun of the Galatea Lab collaborated with scientists from Tokyo Tech to address this challenge. Her research has the potential to transform windows into light-harvesting and sensing devices comprised of a single material in the future. PR Applied published the findings.
Turning tellurite glass into a ‘transparent' light-energy harvester by etching semiconducting patterns using femtosecond laser light. Image Credit: EPFL / Lisa Ackermann
The scientists took an interest in how the atoms in the tellurite glass would reorganize when exposed to fast pulses of high-energy femtosecond laser light. They discovered the formation of nanoscale tellurium and tellurium oxide crystals, both semiconducting materials etched into the glass exactly where the glass had been exposed.
The scientists had an epiphany moment when they realized that exposing a semiconducting substance to daylight could end up in the generation of electricity.
Tellurium being semiconducting, based on this finding we wondered if it would be possible to write durable patterns on the tellurite glass surface that could reliably induce electricity when exposed to light, and the answer is yes. An interesting twist to the technique is that no additional materials are needed in the process. All you need is tellurite glass and a femtosecond laser to make an active photoconductive material.
Yves Bellouard, Associate Professor, Associate Professor in Microengineering at Ecole Polytechnique Fédérale de Lausanne (EPFL)
The EPFL team used their understanding of femtosecond laser technology to alter and examine the impact of the laser on tellurite glass made by Tokyo Tech colleagues. Torun discovered that exposing a 1 cm diameter tellurite glass to UV and visible light could produce a current on its surface and that this current could be generated consistently for months.
Bellouard added, “It is fantastic, we are locally turning glass into a semiconductor using light. We are essentially transforming materials into something else, perhaps approaching the dream of the alchemist!”
Journal Reference
Torun, G., et. al. (2024) Femtosecond-laser direct-write photoconductive patterns on tellurite glass. Physical Review Applied. doi:10.1103/PhysRevApplied.21.014008