Infrared-Emitting Compound With Dihedral-Angle Control
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Solution Overview
Problem
Existing infrared-emitting compounds face challenges in achieving both long wavelength emission and high emission quantum yield due to nonradiative deactivation, particularly in the infrared region, which is crucial for applications like biometric sensing and infrared communication.
Innovation Solution
Introducing a specific substituent into the infrared-emitting compound to create a dihedral angle between aromatic rings, extending the π-conjugate system while suppressing molecular vibration, thereby enhancing emission quantum yield and wavelength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the emission wavelength is extended to longer infrared wavelengths, then the suitability for biometric sensing and infrared communication is improved, but the emission quantum yield decreases due to increased nonradiative deactivation
Solution Approach 1:
The patent applies parameter changes by systematically varying the substituent groups on the squarylium core structure. Specifically, different aromatic substituents (naphthyl, anthracenyl, pyrenyl groups) are introduced at different positions to tune the HOMO-LUMO energy gap, thereby controlling the emission wavelength while maintaining high quantum yield through optimized molecular structure
Solution Approach 2:
The patent creates composite molecular structures by combining the squarylium core with various aromatic substituent groups. These composite structures (squarylium-naphthyl, squarylium-anthracenyl, squarylium-pyrenyl hybrids) leverage the electronic properties of both the core and substituents to achieve long-wavelength emission with high quantum yield, resolving the contradiction between wavelength extension and quantum yield maintenance
2Length of stationary object
If the π-conjugate system is extended to achieve longer emission wavelength, then the emission wavelength is improved, but nonradiative deactivation increases reducing emission quantum yield
Solution Approach 1:
The patent applies local quality by strategically placing electron-donating aromatic substituents at specific positions (R1-R6) on the squarylium core. This localized modification of molecular structure extends the π-conjugate system in controlled regions, allowing wavelength tuning while maintaining structural rigidity and suppressing nonradiative deactivation pathways
Solution Approach 2:
The patent utilizes the planar, rigid structure of aromatic substituents (naphthyl, anthracenyl, pyrenyl groups) that maintain a relatively fixed dihedral angle with the squarylium core. This structural curvature control prevents excessive molecular vibration and rotation, thereby suppressing nonradiative deactivation while extending the π-conjugate system for long-wavelength emission
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 modified compound achieves long wavelength emission with high quantum yield, reducing nonradiative deactivation and concentration quenching in luminescent thin films.
Implementation Method 1
an infrared-emitting compound which enables long wavelength emission and high emission quantum yield
Implementation Method 2
compounds that emit infrared light generally have a problem in that the nonradiative deactivation is apt to occur because the energy difference between the excited state and the ground state is small
Data Source
AI summary
An infrared-emitting compound has a structure represented by the following Formula (1a). In Formula (1a), Ar and ring A each independently represent an aryl ring, a heteroaryl ring or a fused ring thereof. Q-Ar represents an infrared-emitting residue. R1 represents a group in which a dihedral angle between Ar and ring A is 45 degree or more. And a thick line represents a single bond or a double bond.