Window Switching Layer With Fluorescent Dichroic Energy Control
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Solution Overview
Problem
Current devices for regulating energy passage from outdoor to indoor spaces, particularly through windows, face challenges in achieving high light fastness, dichroic ratio, and efficient energy conversion, with existing dyes often lacking stability and suitable absorption in the VIS and NIR ranges.
Innovation Solution
Development of compounds with the formula (I) that incorporate a central subunit of 2-(2,5,7-trithia-1,3-diaza-s-indacen-6-ylidene)malononitrile, offering strong fluorescence, high light fastness, and dichroic properties, along with good solubility in liquid crystalline mixtures, allowing for improved energy absorption and conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing dyes are used in switching layers, then the device can regulate energy passage, but the dyes lack sufficient light fastness and stability under extreme conditions
Solution Approach 1:
The patent modifies the molecular structure of dichroic dyes by changing chemical parameters - specifically incorporating benzothiadiazole and diketopyrrolopyrrole core structures with adjusted substituent groups. This changes the absorption spectrum to extend into the NIR range while maintaining visible range absorption, and improves light fastness through enhanced molecular stability against degradation under extreme conditions.
Solution Approach 2:
The invention creates composite dye molecules combining multiple functional units - benzothiadiazole cores, diketopyrrolopyrrole moieties, and various substituent groups (aromatic, heterocyclic, alkyl chains). This composite molecular architecture achieves synergistic effects: the core structures provide dichroism and absorption properties, while substituent groups enhance solubility in liquid crystal hosts and improve overall stability.
2Productivity
If dyes with strong absorption in VIS and NIR ranges are used, then energy conversion efficiency improves, but the blue-green color range coverage becomes inadequate
Solution Approach 1:
The patent adjusts the HOMO-LUMO energy gap parameters of the dye molecules by modifying the conjugation length and electron-donating/withdrawing groups. This shifts the absorption spectrum to extend further into the NIR range (beyond 780 nm) while maintaining adequate VIS range absorption. The parameter optimization balances NIR absorption strength (for energy conversion) with VIS range coverage (for color appearance).
3Productivity
If dyes with high fluorescence quantum yield are used for energy conversion, then solar cell efficiency improves, but the dyes often absorb at too short wavelengths
Solution Approach 1:
The invention optimizes the fluorescence quantum yield parameter by selecting core structures (benzothiadiazole, diketopyrrolopyrrole) with rigid planar geometries that reduce non-radiative decay pathways. Simultaneously, the conjugation system is extended and tuned to redshift the absorption maximum from the UV/blue region into the VIS/NIR region (450-800 nm), achieving both high quantum yield and appropriate absorption wavelength.
4Ease of operation
If compounds with good solubility in liquid crystalline mixtures are developed, then the switching layer performance improves, but achieving high dichroic ratio and light fastness simultaneously becomes challenging
Solution Approach 1:
The patent applies local quality modification by introducing specific substituent groups at particular positions on the molecular core. The core structure (benzothiadiazole/diketopyrrolopyrrole) maintains dichroic properties and light fastness, while peripheral substituent groups (alkyl chains, aromatic groups, heterocyclic units) are optimized locally to enhance solubility in liquid crystal hosts without compromising the core's functional properties.
Solution Approach 2:
The invention creates composite molecular structures where the rigid aromatic core provides dichroism and stability, while flexible aliphatic chains and polar heterocyclic groups provide solubility and compatibility with liquid crystal matrices. This composite architecture at the molecular level achieves simultaneous optimization of mutually conflicting properties.
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 compounds provide enhanced light stability, high dichroism, and efficient energy conversion, enabling the use of invisible fluorescent light for self-sufficient energy supply in window systems without disruptive visible light effects.
Implementation Method 1
a temperature-induced transition from an isotropic state of the liquid-crystalline medium to a liquid-crystalline state
Implementation Method 2
By applying a voltage to these switching layers, a change in the spatial orientation of the molecules of the dichroic compound can be achieved, which causes a change in their absorption and thus the transmission through the switching layer
Implementation Method 3
the energy absorbed by the dye is partially re-emitted as fluorescent radiation
Implementation Method 4
which in turn is directed to a solar cell, which converts it into electrical energy
Data Source
Figure 1
AI summary
The present invention relates to novel compounds and devices comprising said compounds. The present application also relates to a device for controlling the passage of energy from an exterior to an interior, to windows comprising said device, and uses of said devices and compounds.