a b s t r a c t a r t i c l e i n f o Available online xxxx Keywords: Thermal barrier coating Sol-gel Luminescence Phosphor SensorThis paper investigates the feasibility of manufacturing sol-gel multilayer thermal barrier coatings (TBC) functionalized with different lanthanide ions Ln 3+ having distinct photo-luminescence emission wavelengths (Ln = Sm, Eu, Dy, Er, Tm) for future applications in temperature gradient sensing. Ln 3+ doped 9.75 mol% yttria stabilized zirconia (YSZ) powders were produced to study the effect of activator concentration on luminescence intensity and host matrix crystal structure. Self-quenching was found to limit the maximum signal-to-noise ratio achievable with Sm 3+ , Dy 3+ , Er 3+ and Tm 3+ activators, which was not the case for Eu 3+ in the 1-10 mol% range. The increase in activator was found to affect the crystal structure of YSZ. A solution was proposed that suppressed this effect while significantly increasing the luminescence intensity of all activators. Finally a TBC sensor prototype integrating Eu 3+ , Er 3+ and Dy 3+ doped layers distributed throughout the thickness was successfully deposited by a dip-coating sol-gel process and showed promising through-thickness luminescence sensing capabilities.