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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 liquid porphyrins 19a–19e containing linear alkyl chains.
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Figure 16: Chemical structures of liquid porphyrins 19a–19e containing linear alkyl chains.

Mentions: The groups of Nowak-Król [88] and Maruyama [89] have independently reported a series of room-temperature liquid porphyrins, 19a–19e, by introducing long linear alkyl chains to 5,10,15,20-tetraphenylporphyrin (figure 16). The thermal properties of the compounds were very sensitive to the alkyl chain lengths, with the melting point increasing proportionally to the increase of the chain length. However, a further increase of the chain length (n-C15H31 [89]) would increase the melting point above room temperature, a behavior similar to that of liquid C60 derivatives [86].


Alkyl- π engineering in state control toward versatile optoelectronic soft materials
Chemical structures of liquid porphyrins 19a–19e containing linear alkyl chains.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 16: Chemical structures of liquid porphyrins 19a–19e containing linear alkyl chains.
Mentions: The groups of Nowak-Król [88] and Maruyama [89] have independently reported a series of room-temperature liquid porphyrins, 19a–19e, by introducing long linear alkyl chains to 5,10,15,20-tetraphenylporphyrin (figure 16). The thermal properties of the compounds were very sensitive to the alkyl chain lengths, with the melting point increasing proportionally to the increase of the chain length. However, a further increase of the chain length (n-C15H31 [89]) would increase the melting point above room temperature, a behavior similar to that of liquid C60 derivatives [86].

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.