Upconversion Nanoparticle based Full Color Tactile Sensor

Abstract

Lanthanide doped upconversion nanocrystals (UCNs) release a visible ranged luminescence property under exposed near-infrared (NIR) light by multiphoton excitation. These nanocrystals are highly photochemical stability, absence of background autofluorescence, low toxicity, and large anti-Stokes that orthogonally separate excitation and emission peaks. It also has the advantage of showing various visible range colors through one kind of source. Therefore, UCNs have been studied extensively for applications such as a photodynamic therapy, bioimagings, an UCNs ink of inkjet printer for anti-counterfeit, and a luminescence display. In this work, we rationally utilized the unique optical properties of UCNs and report a new type of colorimetric tactile sensor using rare-earth-doped upconversion nanocrystals. We fabricated full color pixel array using lithography technique and applied this array into the NIR based sensor system to recognize the direction and magnitude of applied pressure.