## 4 Conclusions  
A mica flake (MF) coated with nanosized Y\({}_{2}\)O\({}_{3}\):Eu\({}^{3+}\) (Y\({}_{2}\)O\({}_{3}\):Eu@MF) as a red nanophosphor, was prepared by electrostatic interaction of the particles under hydrothermal conditions. Y\({}_{2}\)O\({}_{3}\):Eu@MF was prepared and optimized by varying the solvent, pH, stirring temperature, calcination temperature, and the loading amount of Y\({}_{2}\)O\({}_{3}\):Eu\({}^{3+}\). The optimized condition for Y\({}_{2}\)O\({}_{3}\):Eu@MF was an 85 \({}^{\circ}\)C stirring temperature, pH 8, 10 wt% of loading amount of the Y\({}_{2}\)O\({}_{3}\):Eu\({}^{3+}\) nanoparticle, and a 650 \({}^{\circ}\)C calcination temperature. In particular, when the loading amount exceeded 10 wt%, the number of nanoparticles coated on MF was reduced. The reason is due to the aggregation of the nanoparticles rather than the interaction and deposition on the surface of MF. The Y\({}_{2}\)O\({}_{3}\):Eu@MF calcined at  
Figure 13: Graph of relationship between gloss at 85\({}^{\circ}\) angle and luminescent property of (**a**) Y\({}_{2}\)O\({}_{3}\):Eu@MF and (**b**) Y\({}_{2}\)O\({}_{3}\):Eu@TMF, and (**c**) optical image of the “KICET” mark prepared pear pigments mixed with epoxy resin under natural light and 254 nm portable UV lamp.  
650 \({}^{\circ}\)C was also stably attached on the mica surface. It was confirmed that the luminescent property of the nanoparticle with low crystallinity caused by milling was recovered by increasing the crystallinity of the coated nanoparticles after the calcination process of Y\({}_{2}\)O\({}_{3}\):Eu@MF. In the case of Y\({}_{2}\)O\({}_{3}\):Eu@TMF, the material prepared at 20 wt% loading amount of the Y\({}_{2}\)O\({}_{3}\):Eu\({}^{3+}\) nanoparticle had the highest coating coverage and was optimized. The photoluminescence spectra revealed the strongest emission peak centered at 611 nm is due to movement of the Eu\({}^{3+}\) ions from the \({}_{5}\)D\({}_{0}\rightarrow\)\({}_{5}\)F\({}_{2}\). In cross-sectional images of FE-SEM, the thickness of the Y\({}_{2}\)O\({}_{3}\):Eu\({}^{3+}\) particles coated on MF or TMF was around 120-270 nm. As a security pigment, the luminescent property of the Y\({}_{2}\)O\({}_{3}\):Eu@MF film was better overall than that of Y\({}_{2}\)O\({}_{3}\):Eu@TMF due to the absorption UV of the TiO\({}_{2}\) layer coated on the MF surface. However, the gloss property of the Y\({}_{2}\)O\({}_{3}\):Eu@TMF film, by TMF having the high reflective layer of TiO\({}_{2}\) coated on MF, was higher compared with that of Y\({}_{2}\)O\({}_{3}\):Eu@MF. Especially, to improve the security level, the Y\({}_{2}\)O\({}_{3}\):Eu@TMF (20 wt%) film was prepared and optimized with red phosphor materials (having luminescent property) and pear materials (having gloss property). Therefore, these materials with luminescent and gloss properties prepared in this work potentially meet their applications for security purposes.  
[PERSON]-[PERSON] and [PERSON] processed the experimental data, performed the analysis. [PERSON]-[PERSON] wrote the manuscript with support from [PERSON], [PERSON] and [PERSON], [PERSON] and [PERSON] contributed to sample preparation. [PERSON] performed the measurements and analyzed the spectra. [PERSON] and [PERSON] helped supervise the project. [PERSON] and [PERSON]-[PERSON] conceived the original idea. All authors provided critical feedback and helped shape the research, analysis and manuscript. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
This work was supported by the Research Fund of Advanced Technology Center (ATC) Project (Project no. 10052088) at Ministry of Trade, Industry and Energy (MOTIE).  
The authors declare no conflict of interest.