High-Capacity Optical Fingerprinting Using Dual-Peak Photoluminescence of Quantum Dots

High Resolution Image Download MS PowerPoint Slide Counterfeiting and unauthorized duplication continue to pose significant threats across industries, ranging from electronics to pharmaceuticals. In response to this challenge, we present a novel optical fingerprinting platform based on cadmium-free CuInS 2 /ZnS quantum dots (QDs), which exhibit a distinctive dual-peak photoluminescence (PL) signature. Time-resolved PL (TRPL) analysis confirms the distinct recombination origins of the two peaks, supporting the assignment to core- and interfacial/shell-related states. Our approach extracts two intrinsically coupled emissions from a single QD type, where both peaks originate within the same nanostructure, making the fingerprint inherently unclonable. This phenomenon enables the generation of rich tunable spectral profiles across a selected range of excitation wavelengths. Using spectral-to-digital processing, we extracted three features from both emission peaks under 10 excitation wavelengths to generate binary fingerprints. The resulting theoretical encoding capacity is estimated to be 1.2 × 10 18 compared to an experimental error probability of ∼3 × 10 –17 . These findings validate the strength and security of the proposed fingerprinting system, highlighting its practical potential for anticounterfeiting applications.