Light Conversion Efficiency of Emitters on Top of Plasmonic and Dielectric Arrays of Nanoparticles

Coupling layers of light emitters to arrays of plasmonic particles provides an opportunity to tailor the photoluminescence, both spectrally and spatially, and opens new venues for the design of phosphors in solid-state-lighting applications. While a significant enhancement of the photoluminescence for certain frequencies and in defined directions has been reported and described in terms of pump enhancement and emission outcoupling, the effect of optical absorption by metals on the conversion efficiency and total photoluminescence intensity is less well studied. Here, we investigate the optical absorption for emitter layers deposited on diffractive arrays of silver and titanium dioxide using an integrating sphere. The results show that absorption at the excitation wavelengths of the emitter has a critical impact on the conversion efficiency, while the absorption at luminescence wavelengths does not modify significantly the total radiation intensity. The evaluation technique used in this manuscript to quantify the optical absorption by the array, leads to a working recipe to design resonant systems that can be exploited in solid-state-lighting applications.