Silane-based wet and plasma coating on SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor for surface modification

To date, organizations in many countries have tried persistent phosphors to apply in the field of safety facilities such as road striping and signs to improve visibility. However, the road facilities were usually exposed to harsh conditions such as pouring and wearing. Therefore, the surface coating and modifications of the phosphor are researched to improve the stability and adhesivity for binder material. Herein, we report the comparison of wet and plasma coating method for surface modification. Three kinds of silane functional materials for coating agent with different characteristic was chosen. From the results, we could confirm that the uniformity of the coating is better in the case of the plasma process. And the plasma-coated phosphor with the coating agent which has long carbon chain maintains the luminescence intensity over 50% after soaking in water for 48h, despite the pristine phosphor almost loses the luminescence characteristics occurring the phase transition.