Synthesis and characterization of PVA/KC/NaYF4:Eu3+ composite fluorescent films

Fluorescent composite films were prepared using polyvinyl alcohol (PVA) as the substrate and NaYF 4 :Eu 3+ phosphors and κ-carrageenan powder (KC) as the fillers by the casting method. The impact of incorporating NaYF 4 :Eu 3+ on the structural, morphological, mechanical property, thermal stability, and optical characteristics of PVA/KC films was examined. The incorporation of KC promoted the formation of hydrogen bonds between KC and PVA. Consequently, the water contact angle of the films increased by approximately 10°, indicating improved water resistance. Meanwhile, the incorporation of NaYF 4 :Eu 3+ increased the thermal stability of the films, with the temperature at 5% mass loss rising by approximately 13°C. Additionally, the mass retention at 600°C improved by 3.47%. Notably, the addition of NaYF 4 :Eu 3+ had a negligible effect on the transparency of the films while imparting fluorescent properties. Under UV excitation at 395 nm, the films exhibited maximum fluorescence intensity at 616 nm, indicating a significant fluorescence effect.