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Alkyl- π engineering in state control toward versatile optoelectronic soft materials

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ABSTRACT

Organic π-conjugated molecules with extremely rich and tailorable electronic and optical properties are frequently utilized for the fabrication of optoelectronic devices. To achieve high solubility for facile solution processing and desirable softness for flexible device fabrication, the rigid π units were in most cases attached by alkyl chains through chemical modification. Considerable numbers of alkylated-π molecular systems with versatile applications have been reported. However, a profound understanding of the molecular state control through proper alkyl chain substitution is still highly demanded because effective applications of these molecules are closely related to their physical states. To explore the underlying rule, we review a large number of alkylated-π molecules with emphasis on the interplay of van der Waals interactions (vdW) of the alkyl chains and π–π interactions of the π moieties. Based on our comprehensive investigations of the two interactions’ impacts on the physical states of the molecules, a clear guidance for state control by alkyl-π engineering is proposed. Specifically, either with proper alkyl chain substitution or favorable additives, the vdW and π–π interactions can be adjusted, resulting in modulation of the physical states and optoelectronic properties of the molecules. We believe the strategy summarized here will significantly benefit the alkyl-π chemistry toward wide-spread applications in optoelectronic devices.

No MeSH data available.


Chemical structures of a HBC derivative 9 (a) and a benzodithiophenen derivative 10 (b), both bearing hydrophobic n-dodecyl and hydrophilic TEG chains.
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Figure 11: Chemical structures of a HBC derivative 9 (a) and a benzodithiophenen derivative 10 (b), both bearing hydrophobic n-dodecyl and hydrophilic TEG chains.

Mentions: The Aida group reported a number of hexa-peri-hexabenzocoronene (HBC) derivatives substituted by both hydrophobic alkyl chains and hydrophilic triethylene glycol (TEG) chains [63, 64]. These molecules, take 9 (figure 11(a)) as an example, self-assembled into well-defined 1D nanotubes stabilized by the π–π interactions of the HBC moieties, vdW interactions of the alkyl chains and hydrophilic interactions governed by the TEG chains. The nanotube was shown to be redox active and had an electrical conductivity of 2.5 MΩ upon oxidation, which was comparable to that of an inorganic semiconductor nanotube based on gallium nitride [65].


Alkyl- π engineering in state control toward versatile optoelectronic soft materials
Chemical structures of a HBC derivative 9 (a) and a benzodithiophenen derivative 10 (b), both bearing hydrophobic n-dodecyl and hydrophilic TEG chains.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036497&req=5

Figure 11: Chemical structures of a HBC derivative 9 (a) and a benzodithiophenen derivative 10 (b), both bearing hydrophobic n-dodecyl and hydrophilic TEG chains.
Mentions: The Aida group reported a number of hexa-peri-hexabenzocoronene (HBC) derivatives substituted by both hydrophobic alkyl chains and hydrophilic triethylene glycol (TEG) chains [63, 64]. These molecules, take 9 (figure 11(a)) as an example, self-assembled into well-defined 1D nanotubes stabilized by the π–π interactions of the HBC moieties, vdW interactions of the alkyl chains and hydrophilic interactions governed by the TEG chains. The nanotube was shown to be redox active and had an electrical conductivity of 2.5 MΩ upon oxidation, which was comparable to that of an inorganic semiconductor nanotube based on gallium nitride [65].

View Article: PubMed Central - PubMed

ABSTRACT

Organic π-conjugated molecules with extremely rich and tailorable electronic and optical properties are frequently utilized for the fabrication of optoelectronic devices. To achieve high solubility for facile solution processing and desirable softness for flexible device fabrication, the rigid π units were in most cases attached by alkyl chains through chemical modification. Considerable numbers of alkylated-π molecular systems with versatile applications have been reported. However, a profound understanding of the molecular state control through proper alkyl chain substitution is still highly demanded because effective applications of these molecules are closely related to their physical states. To explore the underlying rule, we review a large number of alkylated-π molecules with emphasis on the interplay of van der Waals interactions (vdW) of the alkyl chains and π–π interactions of the π moieties. Based on our comprehensive investigations of the two interactions’ impacts on the physical states of the molecules, a clear guidance for state control by alkyl-π engineering is proposed. Specifically, either with proper alkyl chain substitution or favorable additives, the vdW and π–π interactions can be adjusted, resulting in modulation of the physical states and optoelectronic properties of the molecules. We believe the strategy summarized here will significantly benefit the alkyl-π chemistry toward wide-spread applications in optoelectronic devices.

No MeSH data available.