Femtosecond Laser Ablation of Quantum Dot Films toward Physical Unclonable Multilevel Fluorescent Anticounterfeiting Labels

A butterfly-shaped phenothiazine derivative, PTTCN, was synthesized to obtain pure organic porous crystals for the highly efficient absorptive separation of toluene (Tol) and methylcyclohexane (Mcy). Due to the presence of three polar cyano groups and nonplanar conformation, these molecules selfassembled into a hydrogen-bonded organic framework (X-HOF-5) with distinct cavities capable of accommodating Tol molecules through multiple hydrogen-bonding interactions. Upon solvent removal via heating, the activated X-HOF-5 retained its cavity structure albeit with altered stacking arrangements, accompanied by a remarkable fluorescent color change from cyan to green. X-HOF-5a can undergo a phase transformation into X-HOF-5 upon reabsorption of Tol, while exhibiting no accommodation of Mcy due to the weak intermolecular interaction between PTTCN and Mcy. This suggests that the activated HOF material prefers Tol over Mcy. Moreover, X-HOF-5a may selectively accommodate Tol in a Tol/Mcy equimolar mixture, and the purity of Tol can reach 97% after release from the framework. Additionally, it is noteworthy that the HOF material exhibits recyclability without any discernible loss in performance.

Section: ■ Results and Discussionmentioning

confidence: 99%

Luminescent Porous Organic Crystals for Adsorptive Separation of Toluene and Methylcyclohexane

Hu,

Zhao,

Liang

et al. 2024

“…First, the stability of PUF is determined by the intrinsic material properties of the deposited materials. Quantum dots, and perovskite nanocrystals, , for example, can lose their photoluminescence and plasmonic nanoparticles experience distortions in their shapes when heated at elevated temperatures. The second challenge associated with the PUF fabrication by deposition of materials is the ease of delamination of the active layer. , The interfacial strength between the substrate and the active layer determines the stability of PUF.…”

Section: Introductionmentioning

confidence: 99%

Ultradurable Embedded Physically Unclonable Functions

Esidir,

Pekdemir,

Kalay

et al. 2024

Physically unclonable functions (PUFs) have attracted growing interest for anticounterfeiting and authentication applications. The practical applications require durable PUFs made of robust materials. This study reports a practical strategy to generate extremely robust PUFs by embedding random features onto a substrate. The chaotic and low-cost electrohydrodynamic deposition process generates random polymeric features over a negative-tone photoresist film. These polymer features function as a conformal photomask, which protects the underlying photoresist from UV light, thereby enabling the generation of randomly positioned holes. Dry plasma etching of the substrate and removal of the photoresist result in the transfer of random features to the underlying silicon substrate. The matching of binary keys and features via different algorithms facilitates authentication of features. The embedded PUFs exhibit extreme levels of thermal (∼1000 °C) and mechanical stability that exceed the state of the art. The strength of this strategy emerges from the PUF generation directly on the substrate of interest, with stability that approaches the intrinsic properties of the underlying material. Benefiting from the materials and processes widely used in the semiconductor industry, this strategy shows strong promise for anticounterfeiting and device security applications.

“…Physical unclonable functions (PUFs) have emerged as promising anticounterfeiting methods for authentication owing to the inherent unclonability. − A PUF is a system that can generate a unique set of responses to a given challenge (known as challenge-response pairs), using uncontrollable preparation randomness from the internal structure. The reasonable choice of entropy source is crucial for the construction of high security level PUFs.…”

Section: Introductionmentioning

confidence: 99%

Physical Unclonable Functions Based on Photothermal Effect of Gold Nanoparticles

Wang,

et al. 2024

Physical unclonable functions (PUFs) based on uncontrollable fabrication randomness are promising candidates for anticounterfeiting applications. Currently, the most popular optical PUFs are generally constructed from the scattering, fluorescent, or Raman phenomenon of nanomaterials. To further improve the security level of optical PUFs, advanced functions transparent to the above optical phenomenon have always been perused by researchers. Herein, we propose a new type of PUF based on the photothermal effect of gold nanoparticles, which shows negligible scattering, fluorescent, or Raman responses. The gold nanoparticles are randomly dispersed onto the surface of fused silica, which can enhance the photothermal effect and facilitate high contrast responses. By tuning the areal density of the gold nanoparticles, the optimized encoding capacity (2 319 ) and the total authentication error probability (3.6428 × 10 −24 ) are achieved from our PUF due to excellent bit uniformity (0.519) and inter Hamming distances (0.503). Moreover, the intra-Hamming distance (0.044) indicates the desired reliability. This advanced PUF with invisible features and high contrast responses provides a promising opportunity to implement authentication and identification with high security.