Chapter 9
Semiconducting Applications of Polymerizable Liquid Crystals
9.1 Introduction
Since the first demonstration of organic light-emitting diodes (OLEDs) based on conjugated small organics and main-chain polymers [1, 2], interest in the field of organic electronics has expanded enormously with applications in solar cells, plastic electronics as well as displays. Organic photovoltaics (OPVs) are being developed as low-cost, large-area, solar cells; organic field-effect transistors (OFETs) with performance comparable to amorphous silicon devices are expected to be used in flexible, or throwaway electronic applications, such as back-plates for rollable displays or radio-frequency identification (RFID) tags. While some applications remain a distant prospect, others have been commercially realized: OLEDs televisions have been demonstrated and white-light panels based on organic electroluminescence have found markets in architectural lighting. These devices are based on semiconducting and/or light-emitting conjugated organic materials. There is an incentive to develop low-cost and scalable processing methods so that the solution processing of materials is particularly attractive.
In an organic semiconductor, charge-carrier transport, and light-emission depend not only on the orbital energies and wavefunctions of the individual molecules or polymer chains, but also on intermolecular interactions, ...