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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 structures of OPV derivatives 23–24 containing branched alkyl chains. (b) Schematic illustration of the preparation of a solvent-free white-emitting liquid composite using liquid OPV. (c) 5 × 5 cm2 area coated with the white-emitting liquid composite and exposed to UV light (365 nm). (d) Commercially available UV-LED (375 nm) before and after coating with the white-emitting liquid composite. Reprinted with permission from S S Babu et al 2012 Angew. Chem. Int. Edn.51 3391, © 2012 John Wiley & Sons.
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Figure 18: (a) Chemical structures of OPV derivatives 23–24 containing branched alkyl chains. (b) Schematic illustration of the preparation of a solvent-free white-emitting liquid composite using liquid OPV. (c) 5 × 5 cm2 area coated with the white-emitting liquid composite and exposed to UV light (365 nm). (d) Commercially available UV-LED (375 nm) before and after coating with the white-emitting liquid composite. Reprinted with permission from S S Babu et al 2012 Angew. Chem. Int. Edn.51 3391, © 2012 John Wiley & Sons.

Mentions: Based on the designing strategy of C60 liquids, our group extended the π-conjugated C60 unit to an emissive π conjugating system and prepared OPV liquids, 23–24, by substituting two different OPV units with branched alkyl chains (figure 18(a)) [90]. 23–24 are pale yellow fluids at room temperature with low melting points between −43 °C to −55 °C. Similar to the C60 liquids 20–22, OPV liquids with swallow-tailed branched alkyl chains substituting on the (2,4, 6-) positions (i.e. 24) possess much lower viscosity than OPVs with hyper-branched alkyl chains appending on the (3,5-) positions (i.e. 23).


Alkyl- π engineering in state control toward versatile optoelectronic soft materials
(a) Chemical structures of OPV derivatives 23–24 containing branched alkyl chains. (b) Schematic illustration of the preparation of a solvent-free white-emitting liquid composite using liquid OPV. (c) 5 × 5 cm2 area coated with the white-emitting liquid composite and exposed to UV light (365 nm). (d) Commercially available UV-LED (375 nm) before and after coating with the white-emitting liquid composite. Reprinted with permission from S S Babu et al 2012 Angew. Chem. Int. Edn.51 3391, © 2012 John Wiley & Sons.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 18: (a) Chemical structures of OPV derivatives 23–24 containing branched alkyl chains. (b) Schematic illustration of the preparation of a solvent-free white-emitting liquid composite using liquid OPV. (c) 5 × 5 cm2 area coated with the white-emitting liquid composite and exposed to UV light (365 nm). (d) Commercially available UV-LED (375 nm) before and after coating with the white-emitting liquid composite. Reprinted with permission from S S Babu et al 2012 Angew. Chem. Int. Edn.51 3391, © 2012 John Wiley & Sons.
Mentions: Based on the designing strategy of C60 liquids, our group extended the π-conjugated C60 unit to an emissive π conjugating system and prepared OPV liquids, 23–24, by substituting two different OPV units with branched alkyl chains (figure 18(a)) [90]. 23–24 are pale yellow fluids at room temperature with low melting points between −43 °C to −55 °C. Similar to the C60 liquids 20–22, OPV liquids with swallow-tailed branched alkyl chains substituting on the (2,4, 6-) positions (i.e. 24) possess much lower viscosity than OPVs with hyper-branched alkyl chains appending on the (3,5-) positions (i.e. 23).

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.