The power of branched chains: optimising functional molecular materials

Martin J Hollamby,Takashi Nakanishi

doi:10.1039/c3tc31381f

Martin J Hollamby, Takashi Nakanishi

Open Access

https://doi.org/10.1039/c3tc31381f

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Abstract

The power of branched alkyl substituents to alter material properties is known to soft matter chemistry, with examples found in both surfactants and ionic liquids. Here, we highlight their potency in organic molecular/polymeric materials with optoelectronic applications. Attaching branched alkyl chains to the active π-conjugated core modulates core–core interactions and thus softens the material. This can lead to optimised assemblies with improved optoelectronic properties. By increasing the number and volume of the flexible chains, individual cores can be isolated, yielding functional organic liquids with bulk optical properties the same as the intrinsic molecular characteristics obtained for their dilute solutions. These liquid materials can accommodate dopants to offer diverse and tuneable emission colours, and provide an easily applicable flexible and foldable continuous layer for future optoelectronic media.

Highlights

Optoelectronically-active p-conjugated organic molecules or polymers tend to be highly crystalline and have low solubility in most common solvents
Martin Hollamby is a lecturer at Keele University, UK and has held this position since at the end of May 2013
In 2011 Martin was awarded a JSPS postdoctoral fellowship to work in NIMS (National Institute for Materials Science, Tsukuba, Japan) with Dr T

Summary

Introduction

Optoelectronically-active p-conjugated organic molecules or polymers tend to be highly crystalline and have low solubility in most common solvents. Takashi Nakanishi is currently a Principal Researcher at the National Institute for Materials Science (NIMS) in Japan. He completed the doctoral course in shorter period at Nagasaki University, Japan, in 2000. We highlight the advanced control afforded by branched alkyl substituents (e.g. Fig. 1a) in systems with applications in organic optoelectronics This is discussed for both small conjugated molecules and polymers. As detailed branched substituents can signi cantly so en the material This facilitates solution processing, and permits the growth of larger assemblies with improved bulk properties or new functional organic liquids

Molecular assemblies

Polymer assemblies

Functional liquids

Findings

Conclusions