Directing Assembly of Molecular Electronics Inspired by Living Systems

Molecular assembly, crystallization and controlled phase transition have played a central role in the development of modern electronics and energy materials. Recent years, printed electronics based on semiconducting molecular systems have emerged as a new technology platform that promise to revolutionize the electronics and clean energy industry. In contrast to traditional electronic manufacturing that requires high temperature and high vacuum, these new electronic materials can be solution printed at near ambient conditions to produce flexible, light-weight, biointegrated forms at low-cost and high-throughput. However, it remains a central challenge to control the morphology of semiconducting molecular systems across length scales. The significance of this challenge lies in the order of magnitude modulations in device performance by morphology parameters across all length scales.This challenge arises from the fact that directed assembly approaches designed for conventional hard materials are far less effective for soft matters that exhibit high conformational complexity and weak, non-specific intermolecular interactions. On the other hand, biological systems have evolved to assemble complex molecular structures highly efficiently. We are eager to transfer the wisdom of living systems to developing printed electronics technologies as to enable next generation electronics for clean energy and healthcare. In this talk, we present new insights and strategies we recently developed for controlling multi-scale assembly and transformation of semiconducting molecules [1-5]. We learned from living systems and designed bioinspired assembly processes, allowing molecules to put themselves together cooperatively into highly ordered structures otherwise not possible with significantly improved electronic properties. We discovered molecular design rules that impart dynamic and switchable electronic properties through the mechanism of molecular cooperativity – a mechanism ubiquitous in nature. These new solid-state properties could potentially enable new sensing and actuation mechanisms not possible before. We further developed 2D and 3D printing process to realize on-the-fly morphology control down to the molecular and nanoscale.