3D printing of resin composites doped with upconversion nanoparticles for anti- counterfeiting and temperature detection

Rapid prototyping (RP) techniques allow the construction of complex and sophisticated physical models based on personal needs, and the applications of the produced objects can be greatly extended by functionalizing the raw materials (e.g., resins) with components showing electrical, optical and magnetic properties. Here, we demonstrate a simple method for the realization of a three-dimensional architecture through 3D printing of organic resin doped with inorganic upconversion (UC) nanoparticles by using stereolithography technique. In our process, the wet-chemistry derived NaYF4: RE (RE: rare earth) nanoparticles with red, green and blue UC emission were incorporated into a resin matrix. We printed out pre-designed 3D structures with high precision and examined the UC emission properties. In a proof-of-concept experiment, we demonstrate that the 3D printed objects have reliable optical anti-counterfeiting based on high concealment in daylight and multi-color UC emission excited by a near-infrared laser at 980 nm. We also show that the 3D part with UC emission can be used for ratiometric temperature sensing from 303.15 K to 463.15 K, making it possible to map the temperature distribution for studying the thermal diffusion process in complex objects. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement