(7cj) Contorted Molecular Semiconductors for Organic Electronics

Organic semiconductors are promising for light-weight, flexible and bio-compatible electronic devices. The implementation of diverse functions in organic electronics requires chemical engineering to create molecules that go beyond the capability of traditional materials. While conventional wisdom is that planar molecules with strong intermolecular coupling in the solid state are ideal for charge transport, molecules with contorted structures sometimes have superior properties over planar molecules. In this poster, I will present two types of contorted molecules with extraordinary characteristics and applications. First, I will show the property and application of a conjugated macrocycle that consists of diphenyl perylene diimides. This molecule enables us to make ultra-sensitive organic photodetectors with unparalleled detectivity. We elucidate the importance of the cyclic molecular conformation to the high device performance. Second, I will introduce a series of helical, molecular ribbons that act as excellent acceptors in organic solar cells. They are among the best materials for non-fullerene acceptors. Moreover, they are ideal optoelectronic materials for narrowband photodetectors that have narrow spectral response with full­width at half maxima of < 20 nm. This figure-of-merit is comparable to the state­-of­-the-­art narrowband photodetectors made from methylammonium lead trihalide perovskite single crystals. These molecules represent new design motifs of functional organic materials with broad and promising applications. The physical and chemical principles underlying the molecule and device design will be discussed. I will show what we learn from the structure-property relationships and how we make a connection between properties and applications from the molecular aspect.

Research Interests: Organic electronics, Organic-inorganic hybrid nanomaterials, Energy conversion, Ion and charge transport.

Teaching Interests: Materials Chemistry, Nanoscience, Physical chemistry, Electronics.