Conversion of invisible metal-organic frameworks to luminescent perovskite nanocrystals for confidential information encryption and decryption

Abstract

Traditional smart fluorescent materials, which have been attracting increasing interest for security protection, are usually visible under either ambient or UV light, making them adverse to the potential application of confidential information protection. Herein, we report an approach to realize confidential information protection and storage based on the conversion of lead-based metal-organic frameworks (MOFs) to luminescent perovskite nanocrystals (NCs). Owing to the invisible and controlled printable characteristics of lead-based MOFs, confidential information can be recorded and encrypted by MOF patterns, which cannot be read through common decryption methods. Through our conversion strategy, highly luminescent perovskite NCs can be formed quickly and simply by using a halide salt trigger that reacts with the MOF, thus promoting effective information decryption. Finally, through polar solvents impregnation and halide salt conversion, the luminescence of the perovskite NCs can be quenched and recovered, leading to reversible on/off switching of the luminescence signal for multiple information encryption and decryption processes.

Triluminescent Functional Composite Pigment for Non‐Replicable Security Codes to Combat Counterfeiting

“…Different kinds of luminescent materials; lanthanide based luminescent conventional organic dyes, nanomaterials, metal‐organic‐frameworks (MOFs), plasmonic nanomaterials, carbon based quantum dots, semiconductor quantum dots etc. have been explored up to now for the fabrication of security ink to solve the counterfeiting problems ,. Most of the above stated materials have their own pros and cons, which is well investigated in our earlier studies ,,.…”

“…Another, survey by U.S. Department of Commerce estimates that the size of global fake drug market has upto $75 to $200 billion and can occupy half of all trade in developing countries . All these reports poses serious wealth and health threat to consumers globally . Many efforts have been done to secure the official documents, banknotes, pharmaceuticals and high value merchandise from counterfeiting on global level, but the easily availed high‐tech equipment and advanced technologies have made counterfeit easier ,.…”

Highly Luminescent Dual Mode Polymeric Nanofiber‐Based Flexible Mat for White Security Paper and Encrypted Nanotaggant Applications

“…Counterfeiting of valuable documents, high‐value merchandise, currency and branded products has become a threat, which has serious economic, security and health menace for governments, businesses and consumers all over the world . Therefore, each country is trying to use the best security features for the protection of their official documents, banknotes and products, but the availability of modern high‐tech equipment and sophisticated technologies have made it easy to counterfeit .…”

Secret Paper with Vinegar as an Invisible Security Ink and Fire as a Decryption Key for Information Protection

“…PL materials are usually incorporated into a solvent to prepare security inks, which are compatible with printing techniques such as inkjet printing . However, PL security inks still suffer from some drawbacks: 1) the parameters of ink formulations have to be optimized prior to their usage; these parameters include high stability, homogeneous dispersion, suitable solvents, surface tension, concentration, viscosity, wettability, and adhesion to the substrate; 2) some PL security inks containing organic dyes are limited by luminescent quenching and poor photostability; 3) the synthesis of some quantum dots and lanthanide‐doped materials will introduce heavy metals, giving rise to potential toxicity and environmental concerns; and 4) most critically, although PL security inks are invisible to the naked eye under ambient light, they can be easily detected under ultraviolet or near‐infrared light. Thus, the security level of PL security inks needs to be further improved.…”