New Series of Rare-Earth-Based Hybrid Glasses

Metal-organic hybrid glasses have recently emerged as the fourth member in the glass family due to their versatile ability to host various functional ions. These materials combine the excellent optical properties of metal components with the structural diversity of organic materials, showing unique photophysical characteristics. The high transparency, low cost, and high luminous efficiency of hybrid glasses make them promising candidates for optical functional materials. However, no luminescent ions have been successfully introduced into hybrid glasses to date.

Jun Wei and Yuhai Zhang, University of Jinan, China, and colleagues have developed a benign desolvation method, whereby rare-earth-based hybrid glasses (RE(NO₃)₃(C₅H₂N₄)₂ glasses; RE = rare-earth) were rapidly formed within one hour at a low temperature of below 140 °C.This method prevented organic components from breaking down during the melting process and this a facile synthesis was applicable to the full rare-earth family, including Y, Sc, and the lanthanide series. The hybrid glasses showed not only a high transparency but also a high luminescent quantum yield, demonstrating high spatial resolution in X-ray imaging screen.

Hydrogen bonding was found to play a key role in maintaining the structural integrity of the organic-metal framework, which, in turn, promoted the radiative recombination of excited states, including both singlet and triplet states of the organic moiety (4,5-dicyanoiazole, or DCI). An efficient energy transfer from DCI to luminescent lanthanide ions, also known as the antenna effect, was probed using both steady-state and time-resolved spectroscopy. Apart from the luminescent hybrid glasses, the incorporation of inert rare-earth ions such as Y, La, and Lu generated a transparent glass with enhanced room-temperature phosphorescence. This work not only expanded the synthesis toolbox of metal-organic hybrid glasses but also provided an ideal transparent matrix for investigating energy transfer between organic linkers and rare-earth ions.