Inkjet printing of upconversion nanoparticles for anti-counterfeit applications

Abstract

Patterning of upconversion luminescent materials has been widely used for anti-counterfeit and security applications, where the preferred method should be easy, fast, multicolor, high-throughput and designable. However, conventional patterning methods are complex and inflexible. Here, we report a digital and flexible inkjet printing based approach for producing high-resolution and high-luminescence anti-counterfeit patterns. We successfully printed different multicolor luminescent patterns by inkjet printing of upconversion nanoparticles with controlled and uniform luminescence intensity through optimizing the inks and substrates. Combined with another downconversion luminescent material, we achieved two different patterns in the same area, which show up separately under excitation by different wavelength laser sources. The developed technology is promising to use one single substrate for carrying abundant information by printing multilayer patterns composed of luminescent materials with different excitation light sources.

Inkjet Printing of Functional Materials for Optical and Photonic Applications

“…Inkjet printing has also been used in the production of polymeric liquid crystalline optical films showing genuine polarisation effects that can be applied, as disclosed by Moia and Johnson, to the protection of documents or goods [240]. These liquid crystalline prints are only visible under special observation conditions using polarisers, acting as anti-counterfeiting features, as luminescent marks, that can also be obtained by inkjet printing, and are visible under certain light excitation conditions [241,242,243,244,245]. …”

Plasmonic Nanowire‐Enhanced Upconversion Luminescence for Anticounterfeit Devices

“…[17] As luminescence materials, UC nanomaterials have recently been explored with great effort and interest, [17,18] because of their potential use for a wide range of applications such as displays, [19] security inks, [9] solar cells, [20][21][22] and imaging agents. [7] In contrast, UCL based on NIR-to-Vis upconverting nanomaterials is rarely known, and therefore, duplication and/or reuse of devices can be prevented. This is clearly distinguished from a conventional optical transition such as a Stokes shift (i.e., typically UV-to-visible (Vis) downconversion (DC)).…”

Phthalocyanine‐Conjugated Upconversion NaYF4:Yb3+/Er3+@SiO2 Nanospheres for NIR‐Triggered Photodynamic Therapy in a Tumor Mouse Model

“…Recently,u pconversion nanomaterials have shown great promise for av ariety of applications ranging from solar energy conversion [1,2] and security areas [3] and even to biomedicine [4] for nanothermometry, [5] drug delivery, [6] early-stage in vivo bioimaging, [7,8] andt reatment of canceru sing photothermal [9] and photodynamic therapy (PDT). [10,11] PDT is an alternative to conventional treatments,s uch as surgery,c hemotherapy,a nd radiotherapy,d ue to its low toxicity andm inimal side effects on normalcells.…”