A New Transparent Organic Glass with Unity Photoluminescence Quantum Yield

Transparent meltable glasses are keenly desired for making color-conversion layer of Mini-LEDs. In this work, transparent luminescent organic glasses were prepared using a new matrix of heptyltriphenylphosphonium bromide (C₂₅H₃₀BrP, HTPBr). Through doping of a blue dye (9,10-diphenylanthracene, DPA), the resulting glass exhibited a high transparency (92%) and a blue emission at 436 nm. Importantly, the PL QY of glass reached up to nearly unity under 398-nm excitation. X-ray diffraction (XRD) measurement confirmed the amorphous nature of the glass. Thermal characterization revealed a glass transition temperature (T_g) of 28 °C, a melting temperature (T_m) of 178 °C, and a thermal decomposition temperature of 270 °C. Apart from the blue-emitting glass, green- and red-emitting glasses of high transparency were synthesized varied chromophores, including 9,10-bis(phenylethynyl)anthracene (BPEA) and rhodamine B. In a proof-of-concept experiment, these glasses were used to encapsulate UV LEDs via a simple dipping process, which showed a satisfactory color rendering ability. This work brought a new member into the family of transparent luminescent glasses, promising many applications in areas including full-color displays and large-area mini-LED panels.