CdS Quantum Dot Dual-Modal Anti-Counterfeiting Through Photocorrosion
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Solution Overview
Problem
Single-modal photochromic luminescent materials face challenges in safety and forgery difficulty, necessitating the development of multi-modal anti-counterfeiting materials with enhanced security and information storage density.
Innovation Solution
A dual-modal information storage and anti-counterfeiting material is developed using CdS QDs modified by thiol ligands with controllable photocorrosion, applied through spray coating, dip coating, or 3D printing, enabling instantaneous photochromic response and historical fluorescence quenching for pattern retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single-modal photochromic luminescent materials are used for anti-counterfeiting, then the material is simple to synthesize and cost-effective, but the anti-counterfeiting security and forgery difficulty are insufficient
Solution Approach 1:
The patent combines two distinct functional mechanisms into a single material system: (1) photochromic color change for instantaneous information display, and (2) photocorrosion-induced fluorescence quenching for historical pattern retention. This merging transforms a single-modal material into a dual-modal system that simultaneously provides both immediate visual response and permanent historical record, thereby significantly enhancing anti-counterfeiting security while maintaining synthesis simplicity
Solution Approach 2:
The invention uses composite CdS quantum dot materials with controlled photocorrosion properties, combining multiple functional characteristics (photochromism, fluorescence, and controlled degradation) into a single composite material system. This composite approach allows the material to exhibit both instantaneous color change and persistent pattern retention, resolving the contradiction between simplicity and security
2Stability of the object's composition
If photocorrosion of CdS QDs is avoided to maintain fluorescence yield, then material stability is improved, but dual-modal information storage capability cannot be achieved
Solution Approach 1:
The patent precisely controls the photocorrosion parameter by adjusting thiol ligand concentration and UV irradiation conditions. By changing these parameters, the material can operate in different modes: minimal photocorrosion for stability maintenance, or controlled photocorrosion for pattern retention. This parameter control enables the material to switch between stability-prioritized and versatility-prioritized states
Solution Approach 2:
The invention introduces dynamic control over the photocorrosion process through adjustable UV irradiation intensity and duration. The material's fluorescence yield and pattern retention characteristics can be dynamically tuned by varying irradiation conditions, allowing the system to adapt between maintaining stability and achieving versatility based on application requirements
3Reliability
If multi-modal anti-counterfeiting materials are developed to enhance security, then anti-counterfeiting safety is improved, but material complexity and synthesis difficulty increase
Solution Approach 1:
The patent achieves multi-functionality within a single material system: CdS quantum dots simultaneously provide photochromic color change, fluorescence emission, and controlled photocorrosion for pattern retention. This universal material performs multiple anti-counterfeiting functions without requiring separate material layers or complex composite structures, thereby enhancing security while limiting complexity growth
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The material provides enhanced security and information storage density through controllable photocorrosion, allowing for efficient and low-cost dual-modal information storage and anti-counterfeiting applications.
Implementation Method 1
The photocorrosion of CdS QDs will cause a decrease in fluorescence yield, which is usually avoided as a negative factor in the material preparation process. However, the occurrence of photocorrosion is accompanied by alterations in the material's color.
Implementation Method 2
The aforementioned material exhibits not only an instantaneous photochromic response to ultraviolet (UV) light irradiation, but also the ability to retain a historical pattern of partial fluorescence quenching caused by light exposure.
Implementation Method 3
The photocorrosion of CdS QDs will cause a decrease in fluorescence yield. These unique optical characteristics inspired the invention of preparing dual-modal information storage and anti-counterfeiting material by effectively controlling the photocorrosion of CdS QDs.
Data Source
AI summary
A dual-modal information storage and anti-counterfeiting material, and its preparation method are provided. The dual-modal information storage and anti-counterfeiting material uses cadmium sulfide quantum dots (CdS QDs) as information storage material, and uses the controllable photocorrosion of CdS QDs to achieve dual-modal optical information storage and anti-counterfeiting applications. Firstly, the type of ligands and modification degree of CdS QDs are precisely controlled during the aqueous phase synthesise process, so as to effectively control the photocorrosion phenomenon under UV light irradiation. Subsequently, the CdS QDs are loaded in the hydrogel network, and they are also loaded on the substrates such as cloth and paper by spray coating, dip coating or 3D printing, and the information is stored by digital light patterning. Different from the photochromic function of traditional anti-counterfeiting material, the CdS QDs shows dual-modal patterning characteristics in a wide wavelength range.