Photoluminescence and photostability of YVO₄:Eu³⁺ nanoparticle/layered double hydroxide multilayer films prepared via layer-by-layer assembly

Layered double hydroxides (LDHs) consist of positively charged brucite-like layers with interlayer anions for charge compensation. Delaminated cationic LDH nanosheets can be used as building blocks to fabricate functional nanocomposites. In this study, we fabricated photoluminescent multilayer films containing positively charged LDH nanosheets and negatively charged YVO₄:Eu³⁺ nanoparticles on quartz glass substrates through a layer-by-layer assembly technique. The absorbance and photoluminescence (PL) intensity of the YVO₄:Eu³⁺ nanoparticles in the multilayer films were proportional to the number of deposition cycles. These linear relationships indicate that constant amounts of LDH nanosheets and YVO₄:Eu³⁺ nanoparticles were alternately deposited on the substrate. The change in intensity of the 620 nm emission of the YVO₄:Eu³⁺ nanoparticle powder and the multilayer film (LDH/YVO₄:Eu³⁺)₁₀ under continuous 270 nm excitation was measured to compare both photostabilities. The PL intensity of the YVO₄:Eu³⁺ nanoparticle powder decreased to 7% of the initial intensity and then gradually recovered to 19%. In contrast, the PL intensity of the multilayer film (LDH/YVO₄:Eu³⁺)₁₀ decreased to 36% of the initial intensity and then recovered to 139%. The photo-degradation and recovery are discussed.