2D Crossed-Stack Organic Co-Crystals for Bidirectional Charge Transfer

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Solution Overview

Problem

Current supramolecular chemistry lacks the development of two-dimensional (2D) organic charge-transfer complexes that exhibit bidirectional charge transfer and monodomain visible pleochroism, which are essential for advanced optical applications.

Innovation Solution

The creation of a crossed stack system of organic charge-transfer (CT) co-crystals, where one donor molecule shares electrons with two different acceptors in face-to-face and edge-to-face orientations, utilizing non-covalent interactions like charge transfer, π-π stacking, hydrogen bonding, and van der Waals forces to form a 2D supramolecular network with pleochroic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional 1D supramolecular assemblies are used, then molecular organization is achieved, but bidirectional charge transfer and pleochroic properties are not realized

Engineering Contradiction:
Improvecharge transfer capabilityVSAvoidstructural dimensionality
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transitions from conventional one-dimensional (1D) supramolecular assemblies to two-dimensional (2D) crossed-stack architectures. This dimensional change enables bidirectional charge transfer pathways, where electron donors can transfer electrons to multiple acceptors in orthogonal directions, creating the crossed-stack lattice structure that exhibits pleochroic properties. The 2D arrangement allows for complex optical anisotropy that cannot be achieved in 1D systems.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If face-to-face donor-acceptor stacking is used, then charge transfer occurs, but bidirectional charge transfer and pleochroism are not achieved

Engineering Contradiction:
Improveoptical property diversityVSAvoidmolecular arrangement complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs asymmetric molecular arrangements within the crossed-stack lattice, where donor and acceptor molecules are positioned in non-equivalent orientations. This asymmetry creates distinct charge transfer pathways with different optical transitions, enabling pleochroism. The asymmetric stacking allows for direction-dependent optical absorption, where light polarized along different axes experiences different absorption coefficients, producing the observed pleochroic effect.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

By organizing molecules in a 2D crossed-stack architecture rather than simple 1D face-to-face stacking, the patent creates multiple orthogonal charge transfer pathways. This dimensional expansion allows electrons to delocalize in two dimensions and enables optical anisotropy, where the material's optical properties vary with the polarization direction of incident light,从而实现pleochroism.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If simple 1D charge transfer complexes are formed, then electron transfer occurs, but monodomain visible pleochroism is not exhibited

Engineering Contradiction:
Improvecharge transfer efficiencyVSAvoidsupramolecular network dimensionality
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent constructs 2D crossed-stack supramolecular networks that extend conventional 1D charge transfer complexes into the second dimension. This dimensional expansion maintains efficient charge transfer through direct donor-acceptor contacts while introducing optical anisotropy. The 2D architecture creates multiple charge transfer pathways that are spatially separated and orientation-dependent, enabling monodomain visible pleochroism where the material exhibits different absorption spectra for light polarized along different crystallographic axes.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 crossed stack system demonstrates bidirectional charge transfer and visible pleochroism, with optical absorption changing with polarization angle, enabling novel optical applications and showcasing unique electronic and optical phenomena.

Implementation Method 1

bidirectional charge transfer interactions where one donor molecule shares electrons with two different acceptors

Methodology Applied
Scientific EffectCharge transfer:

Implementation Method 2

electron transfer from an electron rich donor to an electron poor acceptor along one dimension

Methodology Applied
Scientific EffectElectron transfer:

Implementation Method 3

pleochroic material whereby the optical absorption continuously changes depending on the polarization angle of incident light

Methodology Applied
Scientific EffectPleochroism: Pleochroism

Implementation Method 4

optical absorption continuously changes depending on the polarization angle

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Implementation Method 5

non-covalent interactions like hydrogen bonding, charge transfer (CT), and n-n stacking

Methodology Applied
Scientific EffectHydrogen bonding:

Implementation Method 6

non-covalent interactions like hydrogen bonding, charge transfer (CT), and n-n stacking

Methodology Applied
Scientific Effectπ-π stacking:

Implementation Method 7

utilizing non-covalent interactions like charge transfer, π-π stacking, hydrogen bonding, and van der Waals forces

Methodology Applied
Scientific EffectVan der Waals forces: Van der Waals Force

Data Source

PatentUS9997271B2Supramolecular networks with electron transfer in two dimensions
Publication Date: 2018.06.12 NORTHWESTERN UNIV

AI summary

Organic charge-transfer (CT) co-crystals in a crossed stack system are disclosed. The co-crystals exhibit bidirectional charge transfer interactions where one donor molecule shares electrons with two different acceptors, one acceptor face-to-face and the other edge-to-face. The assembly and charge transfer interaction results in a pleochroic material whereby the optical absorption continuously changes depending on the polarization angle of incident light.