A method for embedding light-emitting nanoparticles into glass without losing any of their unique properties could be a major step toward smart glass applications, such as 3D volumetric displays, biomedical imaging systems and remote radiation sensors. The "hybrid glass" combines the properties of novel lanthanide-containing upconversion nanoparticles with well-known aspects of glass, such as transparency and the ability to be processed into various shapes including fine optical fiber. Graphic representation of nanoparticles embedded in glass. Courtesy of the University of Adelaide. The research, conducted by the University of Adelaide in collaboration with Macquarie University and University of Melbourne, was published online in the journal Advanced Optical Materials (doi: 10.1002/adom.201600296). "... neuroscientists currently use dye injected into the brain and lasers to be able to guide a glass pipette to the site they are interested in,” said Adelaide researcher Tim Zhao. “If fluorescent nanoparticles were embedded in the glass pipettes, the unique luminescence of the hybrid glass could act like a torch to guide the pipette directly to the individual neurons of interest." The researchers reported a versatile direct-doping approach for integrating bright upconversion nanocrystals in tellurite glass with tailored nanoscale properties. Following a two-temperature glass-melting technique, the doping temperature window of 550 to 625 °C and a 5-min dwell time at 577 °C were determined as the key parameters, balancing the survival and dispersion of the nanocrystals in glass. Although the method was developed with upconversion nanoparticles, the researchers believe their direct-doping approach could be used with other nanoparticles with interesting photonic, electronic and magnetic properties. "If we infuse glass with a nanoparticle that is sensitive to radiation and then draw that hybrid glass into a fiber, we could have a remote sensor suitable for nuclear facilities," said Zhao. To date, the method used to integrate upconversion nanoparticles into glass has relied on the in-situ growth of the nanoparticles within the glass. The researchers said better control over the nanoparticles and glass compositions is necessary to continue developing the technology.