Nondestructive Patterning of Upconverting and Down‐Shifting Luminescent Nanoparticles for Information Encryption

Abstract

Abstract Patterning luminescent colloidal nanoparticles (NPs) at the micro‐ and nanometer scale is crucial for their integration into advanced solid‐state optical, photonic, and electronic devices. However, it remains challenging to achieve high resolution and high fidelity in patterning chemically fragile luminescent NPs, while not sacrificing their structural integrity and/or optical properties. Here, we develop a rationally designed three‐armed diazo crosslinker ( 3G ) for nondestructively patterning various chemically sensitive luminescent NPs with high resolution (down to nanoscale) and high fidelity. The key points of the 3G design include (i) shielding aliphatic C─H bonds, (ii) extending the distance between active sites, and (iii) introducing more crosslinkable moieties. Thanks to the low UV exposure dose (18 mJ cm −2 , in stark contrast to 200–500 mJ cm −2 for diazirine‐based crosslinkers) required for sufficient crosslinking, mild photochemistry of 3G , and proper alignment of energy levels between 3G and NPs, the 3G ‐based patterning method can fully preserve the structural and photophysical properties of both upconverting NPs and perovskite quantum dots, as reflected by their unchanged emission peak/lifetime and high quantum yield retention (90%). Moreover, this method enables the fabrication of multi‐layer structures for dual‐mode anti‐counterfeiting. This work broadens the scope for patterning inorganic NPs, thereby facilitating their potential applications in system‐level devices.