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

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.


(a) Chemical structures of anthracene derivatives 25–26 containing branched alkyl chains and dopants D1 and D2. Photographs of 26 under visible (b) and UV light (365 nm) (c). (d) Photographs of the luminescence color tunability and thermal response of the composites of 25, D1and D2: (i) 25 alone; (ii) 25 + D1 (0.3 mol%); (iii) 25 + D1 (0.5 mol%); (iv) 25 + D2 (2.0 mol%); (v) 25 + D2 (5.0 mol%) and 25 + D1 (0.5 mol%) + D2 (5.0 mol%) at 20 °C (vi); 50 °C (vii) and 100 °C (viii). Adapted from [91] under a Creative Commons Attribution 3.0 Unported (CC BY) license.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 19: (a) Chemical structures of anthracene derivatives 25–26 containing branched alkyl chains and dopants D1 and D2. Photographs of 26 under visible (b) and UV light (365 nm) (c). (d) Photographs of the luminescence color tunability and thermal response of the composites of 25, D1and D2: (i) 25 alone; (ii) 25 + D1 (0.3 mol%); (iii) 25 + D1 (0.5 mol%); (iv) 25 + D2 (2.0 mol%); (v) 25 + D2 (5.0 mol%) and 25 + D1 (0.5 mol%) + D2 (5.0 mol%) at 20 °C (vi); 50 °C (vii) and 100 °C (viii). Adapted from [91] under a Creative Commons Attribution 3.0 Unported (CC BY) license.

Mentions: Right after this achievement, our group synthesized another type of blue-emitting liquid, 25–26 (figure 19(a)), by attaching branched alkyl chains to anthracene-emitting units [91]. Both compounds are yellowish transparent viscous liquids under visible light (figure 19(b)) but show blue luminescence under UV light (figure 19(c)) due to the reduction of π–π interactions through soft alkyl chains substitution. Compound 25, with eight suitable branched alkyl chains, exhibits a lower melting point and viscosity than 26, with only four hyperbranched chains, which is highly consistent with the behaviors of C60 and OPV liquids.


Alkyl- π engineering in state control toward versatile optoelectronic soft materials
(a) Chemical structures of anthracene derivatives 25–26 containing branched alkyl chains and dopants D1 and D2. Photographs of 26 under visible (b) and UV light (365 nm) (c). (d) Photographs of the luminescence color tunability and thermal response of the composites of 25, D1and D2: (i) 25 alone; (ii) 25 + D1 (0.3 mol%); (iii) 25 + D1 (0.5 mol%); (iv) 25 + D2 (2.0 mol%); (v) 25 + D2 (5.0 mol%) and 25 + D1 (0.5 mol%) + D2 (5.0 mol%) at 20 °C (vi); 50 °C (vii) and 100 °C (viii). Adapted from [91] under a Creative Commons Attribution 3.0 Unported (CC BY) license.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 19: (a) Chemical structures of anthracene derivatives 25–26 containing branched alkyl chains and dopants D1 and D2. Photographs of 26 under visible (b) and UV light (365 nm) (c). (d) Photographs of the luminescence color tunability and thermal response of the composites of 25, D1and D2: (i) 25 alone; (ii) 25 + D1 (0.3 mol%); (iii) 25 + D1 (0.5 mol%); (iv) 25 + D2 (2.0 mol%); (v) 25 + D2 (5.0 mol%) and 25 + D1 (0.5 mol%) + D2 (5.0 mol%) at 20 °C (vi); 50 °C (vii) and 100 °C (viii). Adapted from [91] under a Creative Commons Attribution 3.0 Unported (CC BY) license.
Mentions: Right after this achievement, our group synthesized another type of blue-emitting liquid, 25–26 (figure 19(a)), by attaching branched alkyl chains to anthracene-emitting units [91]. Both compounds are yellowish transparent viscous liquids under visible light (figure 19(b)) but show blue luminescence under UV light (figure 19(c)) due to the reduction of π–π interactions through soft alkyl chains substitution. Compound 25, with eight suitable branched alkyl chains, exhibits a lower melting point and viscosity than 26, with only four hyperbranched chains, which is highly consistent with the behaviors of C60 and OPV liquids.

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.