Preface
With the invention of the transistor around the middle of the last century, inorganic semiconductors like Si or GaAs began to take over the role as dominant materials in electronics from the prevailing metals. At the same time, the replacement of vacuum tube-based electronics by solid-state devices initiated a development that by the end of the twentieth century led to the omnipresence of semiconductor microelectronics in our everyday life. Since the beginning of the twenty-first century, we are facing a new electronics revolution that has become possible due to the development and understanding of a new class of materials, commonly known as organic semiconductors. The enormous progress in this field has been driven by the expectation to realize new applications, such as large area, flexible light sources and displays, low-cost printed integrated circuits, or plastic solar cells from these materials.
Strictly speaking, organic semiconductors are not new. The first studies of the dark and photoconductivity of anthracene crystals (a prototype organic semiconductor) date back to the early twentieth century. Later on, triggered by the discovery of electroluminescence in the 1960s, molecular crystals were intensely investigated by many researchers. These investigations could establish the basic processes involved in optical excitation and charge carrier transport. Nevertheless, in spite of the principal demonstration of an organic electroluminescent diode incorporating even ...
