Enhancement of light extraction in Y3Al5O12:Tb3+ thin films through nanopatterning

Abstract

Light extraction is a key parameter to improve the performances of optical devices. Nanopatterned Y 3 Al 5 O 12 :Tb 3+ luminescent coatings usable in such devices have been elaborated and have shown enhanced emission efficiency compared to their unpatterned counterparts. These nanostructured films were obtained by using the colloidal lithography combined with the Langmuir-Blodgett technique. It is the first time to our knowledge that this patterning technique is directly applied on YAG matrix. Resulting nanostructuring is a hexagonal network capable of modifying the light travelling path within the substrate. Conventional and angular-resolved photoluminescence were investigated on both unpatterned and patterned samples. Due to the nanostructuring, the extraction efficiency is improved by 26% and 131% depending on the crystallinity of the sample. Noticeably, nanostructuring is found to have an influence on the angular distribution of photoluminescence whose intensity has been evaluated to its maximum normal to the film surface.

Nanoantennas Patterned by Colloidal Lithography for Enhanced Nanophosphor Light Emission

“…Colloidal lithography, also known as nanosphere lithography, allows preparing large-area nanostructures in an inexpensive way using a monolayer of self-assembled spheres as an evaporation mask . In the particular case of phosphor materials, this method has been employed to pattern thick and thin yttrium aluminum garnet phosphor layers to enhance the emission. , Known for decades, this method is widely used for the fabrication of periodic arrays of metallic nanostructures due to its simplicity and versatility, as well as its low cost compared to the other lithographic techniques . However, the combination of optical antennas attained by colloidal lithography and thin phosphor films has not been reported in the field.…”