Chapter 2
Self-Organized Semiconducting Discotic Liquid Crystals for Optoelectronic Applications
2.1 Introduction
Why are almost all of the leaves on earth green? Because they have a superior light harvesting material, i.e., chlorophyll, to efficiently absorb sunlight for photochemical reactions. This material evolved to be the best for the above purpose since it was produced after hundreds of millions of years' natural selection. Interestingly, the key component of chlorophyll is porphyrin, a disc-like aromatic molecule with a large π-conjugated system. In many cases, when large π-conjugated aromatic cores are linked with flexible aliphatic peripheral substituents, a discotic liquid crystalline (DLC) phase may appear. Since the work of Chandrasekhar on the hexaesters of benzene published in 1977 [1], DLC materials have been investigated intensively, especially over the last decade. Successful commercialization of DLC materials has been accomplished in Fuji “Wide-View” (WV) optical compensation films [2, 3]. Apart from the use in display, they have been widely and deeply investigated starting from structure–properties to structure–device performance relationships.
In recent decades, there has been increasing attention in the research field of organic electronics for device applications such as photovoltaic devices (PVD), light-emitting-diodes (LEDs), field-effect transistors (FETs), memory ...
