Donor-Acceptor Complex for Solid-State Fluorescence
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Solution Overview
Problem
Conventional light-emitting organic materials experience reduced light emission efficiency in the solid state due to energy attenuation from neighboring molecules, making it challenging to develop materials that intensely emit light both in solution and solid states.
Innovation Solution
A novel donor-acceptor type organic optical material is created by reacting a pi-conjugated system with a compound having proton donating or electron pair accepting properties, such as a Bronsted acid, to form a complex that exhibits non-covalent interactions and maintains high light emission efficiency in both solution and solid states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If highly planar molecules are used as light emitting organic materials, then light emission intensity is improved in solution state, but light emission efficiency drastically reduces in solid state due to energy attenuation from neighboring molecules
Solution Approach 1:
The patent introduces methyl groups at specific positions (2 and 6) of the pyridine ring to create local steric hindrance. This local structural modification prevents close contact between neighboring molecules in the solid state, thereby reducing energy attenuation while maintaining the overall planar structure needed for light emission. The local quality change (adding methyl groups) resolves the contradiction between maintaining planarity for emission intensity and preventing molecular contact for energy loss reduction.
Solution Approach 2:
The patent creates an asymmetric molecular structure by adding methyl groups to specific positions on the pyridine ring rather than maintaining perfect symmetry. This asymmetric design with methyl substituents at positions 2 and 6 disrupts the uniform packing of molecules in the solid state, reducing the efficiency of energy transfer between neighboring molecules while preserving the conjugated system for effective light emission.
2Productivity
If robust and highly planar molecules are used, then light emission efficiency is improved in solution, but molecular contact and interference increase in solid state reducing emission efficiency
Solution Approach 1:
The patent applies local quality modification by introducing methyl groups at specific positions (2 and 6) of the pyridine ring. This local structural change creates steric hindrance that prevents harmful molecular interference in the solid state while maintaining the overall robust and planar structure necessary for high light emission efficiency in both solution and solid states.
3Adaptability or versatility
If conventional light emitting organic materials are used in solid state, then application requirements are met, but light emission intensity reduces due to neighboring molecule influence
Solution Approach 1:
The patent uses local quality modification by adding methyl groups at positions 2 and 6 of the pyridine ring to create steric hindrance. This allows the material to maintain application suitability in solid state while preventing molecular interference that would otherwise reduce light emission intensity, thus resolving the contradiction between adaptability and illumination intensity.
Solution Approach 2:
The asymmetric structure created by methyl substitution at specific positions enables the material to function in solid state applications while disrupting the uniform molecular arrangement that causes energy attenuation, thereby maintaining high light emission intensity across different application states.
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 complex achieves strong fluorescence intensity, longer maximum emission wavelength, higher fluorescence quantum yield, and prolonged fluorescence lifetime, making it suitable for various optical applications including organic LEDs, lasers, and solar cells.
Implementation Method 1
fluorescent organic compounds which emit light by irradiation with X-ray, ultraviolet ray, or visible light
Implementation Method 2
intensely emit light not only in a solution state but in a solid state
Implementation Method 3
a complex is easily produced at the electron accepting site through a non-covalent interaction
Implementation Method 4
exhibits a property of emitting light having a maximum fluorescence wavelength which causes a Stokes shift
Data Source
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AI summary
Provided is a novel donor-acceptor type compound which emits light even in a solid state. The present invention provides an organic optical material comprising a complex formed from (1) a conjugated molecule having (a) at least one electron donating site, (b) at least one electron accepting site, and (c) at least one conjugated site in the same molecule and (2) a compound having a proton donating property or an electron pair accepting property, the complex having a non-covalent interaction at the electron accepting site, wherein the complex is solid at ordinary temperature; and the organic optical material has a property of emitting light having a maximum fluorescence wavelength which causes a Stokes shift having a value corresponding to 5% or more of the value of a maximum absorption wavelength from the maximum absorption wavelength toward the long wavelength side.