Self-sorted systems offer a great degree of control when making well defined multi-component systems for applications such as p-n heterojunctions for organic electronic devices. These systems need this controlled self-assembly to ensure recombination of charge separated states generated in the material does not occur. Recombination of charges makes the material less efficient. Organic-based electronic devices offer potentially cheaper and more easily processed materials compared to traditional inorganic based alternatives. The use of organic materials also offers a huge range of functionality and structures that can be investigated for different applications such as solar cells by tuning the light absorption profile and the HOMO-LUMO gap. Here, we describe the use of gelation as a method to control the self-assembly pathway of a mixed system of a low molecular weight gelators. We use a n-type perylene bisimide gelator and a p-type stilbene gelator. The use of a controlled, slow pH drop using the hydrolysis of glucono-δ-lactone to gluconic acid allows the molecules to self-sort into fibres of either only p-type or only n-type gelators (Fig. 1a-c). These self-assembled molecules are stabilised by H-bonding and π-π stacking. These fibres then further entangle with each other, not only to form a self-supporting hydrogel but also a p-n heterojunction where the fibres meet (Fig. 1d-e). When processed, the self-sorted material is photoresponsive and is able to form charge separated states using visible light.

Self-sorted multi-component photoconductive gels

253rd National Meeting (2017)

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