Stochastic Orientational Encoding via Hydrogen Bonding Driven Assembly of Woven-Like Molecular Physically Unclonable...

Area of Science:

• Materials Science
• Nanotechnology
• Organic Electronics

Background:

• Counterfeiting necessitates advanced security features and object authenticity verification.
• Physically unclonable functions (PUFs) offer a promising solution, but require higher encoding capacities and multi-level responses.
• Existing PUF systems often lack the integration of molecular definition and single-material processing.

Purpose of the Study:

• To develop a novel stochastic orientational encoding approach for ultrahigh-capacity physically unclonable functions (PUFs).
• To demonstrate a facile, solution-processed method for fabricating molecular thin films with advanced encoding capabilities.
• To explore the potential of molecular design and noncovalent interactions in creating single-material PUFs.

Main Methods:

• Fabrication of a nanoscopic thin film using rod-shaped oligo(p-phenyleneethynylene) (OPE) π-architecture via ambient-atmosphere solution processing.
• Utilizing directional hydrogen-bonding and C─H···π contacts for energetically favorable uniaxial molecular assembly and crystal growth.
• Employing solvent vapor annealing to induce dewetting and 1D random crystallization, creating woven-textured random features.
• Applying convolutional neural networks to analyze microcrystal domain variations and stochastic 1D crystal orientations for artificial coloration.

Main Results:

• Achieved an ultrahigh encoding capacity of (6.5 × 10⁴)^{(2752 × 2208)} through stochastic orientational encoding.
• Demonstrated a single-material thin film system capable of generating artificial coloration based on molecular assembly and crystallization.
• Successfully implemented a facile, low-cost, solution-processed fabrication method suitable for mass production.

Conclusions:

• The developed stochastic orientational encoding strategy offers an effective approach for achieving ultrahigh encoding capacities in single-material thin films.
• This method enables low-cost, solution-processed fabrication, promoting broad adoption of molecular PUFs.
• Opens new avenues for exploring molecular PUFs through tailored structural design and engineering of noncovalent interactions.