Boron Squarylium Infrared Absorbent for Robustness and Invisibility
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Solution Overview
Problem
Current infrared absorbents either lack invisibility or robustness, as cyanine methine pigments are prone to decomposition and vanadylphthalocyanine pigments are not invisible enough, necessitating a material with both high infrared absorbability and invisibility.
Innovation Solution
A boron atom-containing squarylium compound is developed, which shifts absorption peaks to a higher wavelength range, providing superior invisibility and robustness by introducing a boron atom into a conventional squarylium compound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cyanine methine pigments are used as infrared absorbents, then invisibility is improved, but robustness deteriorates due to decomposition from long methine conjugated chains
Solution Approach 1:
The invention changes the chemical structure parameters by replacing the traditional methine conjugated chain with a squarylium core structure containing boron atoms. This structural parameter change maintains the infrared absorption capability while eliminating the decomposition issue of long methine chains, thus improving robustness while preserving invisibility
Solution Approach 2:
The invention creates a composite molecular structure by combining squarylium core with specific substituents (R1-R4 groups) that contain boron atoms. This composite structure integrates the stability of the squarylium core with the optical properties needed for infrared absorption and invisibility, resolving the contradiction between robustness and invisibility
2Reliability
If vanadylphthalocyanine pigments are used as infrared absorbents, then robustness is improved, but invisibility deteriorates
Solution Approach 1:
The invention changes the optical parameters by adjusting the conjugation length and electron distribution in the squarylium structure through boron atom incorporation and specific substituent selection. This allows tuning the absorption spectrum to achieve better invisibility while maintaining the robustness provided by the stable squarylium core structure
3Reliability
If conventional squarylium compounds are used, then invisibility and robustness are improved, but infrared absorbability in higher wavelength range is insufficient
Solution Approach 1:
The invention changes the energy level parameters by introducing boron atoms into the squarylium structure, which modifies the HOMO-LUMO energy gap. This parameter change extends the absorption wavelength into the higher infrared range (700-1200 nm) while preserving the robustness and invisibility characteristics of the squarylium core
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 boron atom-containing squarylium compound exhibits enhanced infrared absorbability with maximum peaks in the 700 nm to 1200 nm range, maintaining high robustness and invisibility, suitable for various applications including optical films and security inks.
Implementation Method 1
The boron atom-containing squarylium compound exhibits enhanced infrared absorbability with maximum peaks in the 700 nm to 1200 nm range
Data Source
AI summary
Provide is a compound having absorbability in an infrared region, excellent invisibility and robustness. The compound is a squarylium compound represented Formula (1):wherein, R1 and R2 represent an alkyl group, cycloalkyl group, aryl group, or heteroaryl group, which may be substituted by a substituent; R3 and R4 represent a hydrogen atom or alkyl group; X1 and X2 represent an oxygen atom or —NR5—, in which R5 represents a hydrogen atom or alkyl group; Y1, Y2, Y3 and Y4 represent a halogen atom, alkyl group, cycloalkyl group, aryl group, heteroaryl group, arylcarbonyloxy group, or alkylcarbonyloxy group; a plurality of Y1's, Y2's, Y3's, or Y4's may be bonded to form a ring structure, respectively; Y1 and Y2, or Y3 and Y4 may be bonded to form a ring structure; n1 and n4 represent an integer of 0 to 3; and n2 and n3 represent an integer of 0 to 2.