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

Abstract

Fluorescent composite films were prepared using polyvinyl alcohol (PVA) as the substrate and NaYF₄:Eu³⁺ phosphors and κ-carrageenan powder (KC) as the fillers by the casting method. The impact of incorporating NaYF₄:Eu³⁺ 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 NaYF₄:Eu³⁺ 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 NaYF₄:Eu³⁺ 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.