Electronic Process in Organic Solids

Abstract

Organic solids, in a broad sense, include all solid state materials consisting of organic molecules or polymers, namely, compounds with carbon atoms as their essential structural elements [1] . Under this generic term, the category of organic solids covers a wide variety of natural solids such as wood and cotton, and industrial products such as plastics and rubber, many of which are insulators. The scope of this book, however, will be confi ned to the class of organic solids that can serve as active components in electronic or photonic devices. The functionalities of these materials are mainly based on their capability to carry and transport charges and neutral excitations. For simplicity, hereafter the term “ organic solid ” will refer specifi cally to those organic materials showing (semi)conductor properties in the form of crystals, thin fi lms, or glassy state. Electronic process in organic solids determines the properties of the materials and their potential applications in optoelectronic devices. It is a very complicated process, and has a close relationship with molecular electronic structures, molecular interactions, charge – charge coupling, charge – photon coupling, and exciton – photon coupling, and so on. Consequently, chemists fi nd it diffi cult to understand due to the complication of electronic process in organic solids. At this point, electronic process will be expounded from the chemist ’ s perspective in order to appreciate the basic concepts and the nature of this complicated process.