Room-temperature synthesis of Ce/Tb/Na-codoped CaF2 and SrF2 luminescent nanocrystals with a photoluminescence quantum yield of 60%

Abstract

Rare earth-doped fluoride luminescent nanocrystals have high potential for application in bio-imaging, anti-counterfeiting, photovoltaics, solid state lighting, and high-quality displays. However, the synthesis of rare earth-doped fluoride luminescent nanocrystals usually requires complex experimental operation, high-temperature reactions, and ultra-long reaction times. Here, we have developed a facile, room-temperature, and rapid synthetic method to prepare highly luminescent and dispersible Ce/Tb/Na-codoped CaF₂ and SrF₂ nanocrystals. The resulting nanocrystals exhibit extremely small sizes (4.8 nm for CaF₂ and 6.2 nm for SrF₂) and high photoluminescence quantum yields (39% for CaF₂ and 60% for SrF₂). The study also highlighted the environmental benefits of the synthesis method, providing a green, fast, and cost-effective approach to produce rare earth ion-doped fluoride luminescent materials with high potential application in high-quality displays, anti-counterfeiting technologies, bioimaging, and photovoltaics.