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

Area of Science:

• Materials Science
• Nanotechnology
• Photochemistry

Background:

• Micro- and nanoscale patterning of luminescent nanoparticles (NPs) is essential for optical, photonic, and electronic devices.
• Existing methods struggle to pattern chemically fragile NPs with high resolution and fidelity without compromising their properties.

Purpose of the Study:

• To develop a novel crosslinker for non-destructive, high-resolution patterning of chemically sensitive luminescent NPs.
• To preserve the structural integrity and optical properties of patterned NPs.

Main Methods:

• Design and synthesis of a three-armed diazo crosslinker (3G) with shielded C-H bonds and multiple crosslinkable moieties.
• Utilizing mild photochemistry with a low UV exposure dose (18 mJ cm⁻²) for crosslinking.
• Patterning various luminescent NPs, including upconverting NPs and perovskite quantum dots.

Main Results:

• Achieved high-resolution patterning down to the nanoscale with high fidelity.
• Preserved structural and photophysical properties of NPs, evidenced by unchanged emission characteristics and 90% quantum yield retention.
• Demonstrated the fabrication of multi-layer structures for dual-mode anti-counterfeiting applications.

Conclusions:

• The 3G crosslinker offers a mild and effective method for patterning sensitive luminescent inorganic NPs.
• This technique facilitates the integration of NPs into advanced system-level devices.
• Expands the possibilities for NP patterning in anti-counterfeiting and other applications.