Advanced ion-exchangeable materials

Researches conducting by the group focuses on the development advanced ion-exchangeable optical materials for overcoming new challenges in optics, photonics, and sensorics.    
One of the challenges is development phosphors based on silver clusters. Glasses with luminescent silver clusters can be used as phosphors for warm-white LEDs, down-convertors for solar cells, and flexible screen monitors. We have optimized glass composition, parameters of an ion exchange process (silver content, temperature, and duration) and heat treatment (temperature and duration). As a result special optical glass for formation of highly luminescent silver clusters with the ion exchange method was developed. Silver clusters in the glass reveal broadband emission in the visible and NIR ranges under UV excitation. Photoluminescence quantum yield of silver clusters as high as 65%, which in two times exceeds efficiency of ever-developed glasses with silver clusters. 
 
Influence of heat treatment temperature on the luminescence of silver clusters formed in ion-exchanged glasses. The photo made under excitation of a mercury lamp
 
Influence of ion exchange duration on the luminescence of silver clusters formed in ion-exchanged glasses. The duration changes from left to right from 1 minute up to 21 hours. The photo made under excitation of a mercury lamp
 
Today the group aims at developing phosphors based on glass co-doped with silver clusters and rare earth ions. Rare earth ions well known to possess weak and narrow absorption bands that limit their applications in some fields. On the other hand, silver clusters could enhance luminescence of rare earth ions owing to energy transfer. Already developed Eu-doped glass reveals excitation of Eu3+ ions emission at any wavelength in the range between 260-425 nm. Morover, intensity of Eu3+ emission greatly exceeds that in the glass with no clusters.
 
Photo of glass samples co-doped with silver clusters and europium. Eu2O3 content increases from left to right (0, 0.1 и 0.5 % mol). The photo made under excitation of a mercury lamp
 
Today silver nanoparticles are promising material for sensorics. Nanoparticles formed on the surface of glass can be used as sensitive element of sensors based on surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS) phenomena. Such sensors are extremely sensitive to many chemical or biological analytes and diseases (for example, cancer, Alzheimer’s disease, and Parkinson’s disease) and able to detect even single molecule. Currently, the group “Advanced ion-exchangeable materials” is developing a new technology for synthesizing plasmon-coupled silver nanoparticles on surface of silicate glasses for SPR- and SERS-based sensors.
 
Raman spectrum of a dried drop of Rhodamine 6G aqueous solution (8*10-7 mol/l) deposited on a glass surface with silver nanoparticles

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