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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.


(a) Chemical structure of an alkylated-C603a. (b) SEM image of globular microparticles with nanoflaked outer surfaces formed by cooling a 1,4-dioxane solution of 3a from 70 °C to 20 °C and a photograph (inset) of a water droplet on the surface of a thin film of the globular micro-objects on a Si substrate. Reprinted with permission from T Nakanishi et al 2008 Adv. Mater.20 443, © 2008 John Wiley & Sons. (c) SEM image of Au nanoflakes transcribed from the nanoflake-featured microparticles of 3a. Reprinted with permission from Y Shen et al 2009 Chem. Eur. J.15 2763, © 2009 John Wiley & Sons. Morphology of 3a-SWCNT assembly before (d) and after (e) NIR light laser irradiation (λ = 830 nm). Reprinted with permission from Y Shen et al 2010 J. Am. Chem. Soc.132 8566, © 2010 American Chemical Society. Morphology and anti-wettability of 3a-AuNPs before (f) and after (g) visible light laser irradiation (λ = 532 nm). Reprinted with permission from H Asanuma et al 2013 Langmuir129 7464, © 2013 American Chemical Society.
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Figure 4: (a) Chemical structure of an alkylated-C603a. (b) SEM image of globular microparticles with nanoflaked outer surfaces formed by cooling a 1,4-dioxane solution of 3a from 70 °C to 20 °C and a photograph (inset) of a water droplet on the surface of a thin film of the globular micro-objects on a Si substrate. Reprinted with permission from T Nakanishi et al 2008 Adv. Mater.20 443, © 2008 John Wiley & Sons. (c) SEM image of Au nanoflakes transcribed from the nanoflake-featured microparticles of 3a. Reprinted with permission from Y Shen et al 2009 Chem. Eur. J.15 2763, © 2009 John Wiley & Sons. Morphology of 3a-SWCNT assembly before (d) and after (e) NIR light laser irradiation (λ = 830 nm). Reprinted with permission from Y Shen et al 2010 J. Am. Chem. Soc.132 8566, © 2010 American Chemical Society. Morphology and anti-wettability of 3a-AuNPs before (f) and after (g) visible light laser irradiation (λ = 532 nm). Reprinted with permission from H Asanuma et al 2013 Langmuir129 7464, © 2013 American Chemical Society.

Mentions: Similar self-assembly phenomenon using a heating/cooling process in 1,4-dioxane was observed for an alkylated C60 derivative, 3a, bearing 3,4,5-triseicosyloxyl chains (figure 4(a)), which also formed globular objects with wrinkled nanoflake structures at the outer surface (figure 4(b)) [30]. The extraordinarily high roughness, together with the hydrophobic properties of both the C60 and alkyl chains, made the fabricated thin film of these globular microparticles exhibit superhydrophobicity with a water contact angle of 152° (figure 4(b), inset). The surface morphology and superhydrophobicity of the thin film is reminiscent of the self-cleaning features of the Lotus leaves.


Alkyl- π engineering in state control toward versatile optoelectronic soft materials
(a) Chemical structure of an alkylated-C603a. (b) SEM image of globular microparticles with nanoflaked outer surfaces formed by cooling a 1,4-dioxane solution of 3a from 70 °C to 20 °C and a photograph (inset) of a water droplet on the surface of a thin film of the globular micro-objects on a Si substrate. Reprinted with permission from T Nakanishi et al 2008 Adv. Mater.20 443, © 2008 John Wiley & Sons. (c) SEM image of Au nanoflakes transcribed from the nanoflake-featured microparticles of 3a. Reprinted with permission from Y Shen et al 2009 Chem. Eur. J.15 2763, © 2009 John Wiley & Sons. Morphology of 3a-SWCNT assembly before (d) and after (e) NIR light laser irradiation (λ = 830 nm). Reprinted with permission from Y Shen et al 2010 J. Am. Chem. Soc.132 8566, © 2010 American Chemical Society. Morphology and anti-wettability of 3a-AuNPs before (f) and after (g) visible light laser irradiation (λ = 532 nm). Reprinted with permission from H Asanuma et al 2013 Langmuir129 7464, © 2013 American Chemical Society.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 4: (a) Chemical structure of an alkylated-C603a. (b) SEM image of globular microparticles with nanoflaked outer surfaces formed by cooling a 1,4-dioxane solution of 3a from 70 °C to 20 °C and a photograph (inset) of a water droplet on the surface of a thin film of the globular micro-objects on a Si substrate. Reprinted with permission from T Nakanishi et al 2008 Adv. Mater.20 443, © 2008 John Wiley & Sons. (c) SEM image of Au nanoflakes transcribed from the nanoflake-featured microparticles of 3a. Reprinted with permission from Y Shen et al 2009 Chem. Eur. J.15 2763, © 2009 John Wiley & Sons. Morphology of 3a-SWCNT assembly before (d) and after (e) NIR light laser irradiation (λ = 830 nm). Reprinted with permission from Y Shen et al 2010 J. Am. Chem. Soc.132 8566, © 2010 American Chemical Society. Morphology and anti-wettability of 3a-AuNPs before (f) and after (g) visible light laser irradiation (λ = 532 nm). Reprinted with permission from H Asanuma et al 2013 Langmuir129 7464, © 2013 American Chemical Society.
Mentions: Similar self-assembly phenomenon using a heating/cooling process in 1,4-dioxane was observed for an alkylated C60 derivative, 3a, bearing 3,4,5-triseicosyloxyl chains (figure 4(a)), which also formed globular objects with wrinkled nanoflake structures at the outer surface (figure 4(b)) [30]. The extraordinarily high roughness, together with the hydrophobic properties of both the C60 and alkyl chains, made the fabricated thin film of these globular microparticles exhibit superhydrophobicity with a water contact angle of 152° (figure 4(b), inset). The surface morphology and superhydrophobicity of the thin film is reminiscent of the self-cleaning features of the Lotus leaves.

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.