The field of organic electronics is entering its commercial phase. The recent market introduction of the first prototypes based on organic transistors fabricated from solution is set to augment the existing market presence of organic light-emitting diode applications. Organic photovoltaic products are not far behind. In this article, we provide a brief overview of these devices, with our main focus being organic transistor applications. In particular, we examine some of the key performance requirements for working devices. We also review some of the important advances in semiconductor design and device fabrication techniques and discuss some of the technical challenges that remain in the optimization of next-generation products.

Organic light-emitting devices (OLEDs) have been widely developed for flat-panel displays, but only recently the efficiency of white OLEDs has risen to the point where they can be considered for solid-state lighting (SSL) applications. In this review, we discuss the requirements of solid-state lighting as they relate to OLEDs. We focus on how the color, efficiency, and cost requirements of general illumination differ from those of displays and how these differences might have an impact on the design of organic SSL. We then present some recent developments in large-area fabrication techniques that might be appropriate for solid-state lighting applications. Finally, we review recent results in the development of organic materials, device architectures, light extraction schemes, and fabrication techniques that can lead to cost-effective OLED lighting.

Organic solar cells, based on polymer/fullerene-blend films, are advancing rapidly toward commercial viability. In this article, we review recent progress on two issues critical for technological applications: device photovoltaic efficiencies and processing technologies for high-throughput production. In terms of device efficiencies, we consider advances in low-bandgap polymers, film morphology, and device structure aimed at increasing efficiencies beyond 5%. We then review recent progress in developing high-throughput, solution-printing-based processes for low-cost device fabrication.

Organic field-effect transistors (FETs) are currently the focus of significant academic research and industrial development interest, as they potentially offer unique advantages over their inorganic counterparts in terms of cost reductions, compatibility with low-temperature and printing-based manufacturing, and potentially even performance. The first generation of products incorporating organic FETs is presently being introduced to the market. This article provides an overview of strategies for achieving high field-effect mobilities in solution-processed organic semiconductor films. We provide an assessment of materials challenges to meet performance and reliability requirements for a range of display and circuit applications and present an overview of state-of-the-art application demonstrations in active-matrix addressing of flexible eletrophoretic, organic light-emitting diode, and liquid-crystal displays, as well as radio-frequency identification tagging. We discuss how the unique functional properties of organic semiconductors, which allow comparatively easy integration of information processing, information storage, light emission, and light detection functions, might enable multifunctional applications that are not easy to create with other material systems.

An overview of recent work on the connection between electrical and molecular properties of semiconducting polymers for thin-film transistors (TFTs) is presented. A description of the molecular packing and microstructure of amorphous to semicrystalline semiconducting polymers is presented. The features of basic models for electrical transport in TFTs are discussed. These studies indicate that defect states and traps are as important as ordered domains for understanding transport in semiconducting polymers. Advanced methods, such as electric force microscopy, useful for measuring the characteristics of defect states and charge traps, are briefly reviewed.

We discuss some recent advances in the use of organic semiconductor devices with additional or enhanced functionality beyond simple electrical switching. These include diodes that act as local temperature sensors or that filter reverse-bias currents at tens of megahertz frequency. Transistors are described with a range of sensing and reporting functions, for such properties as pressure, magnetic field, and chemical vapor. Because these devices will likely be employed in arrays and assemblies, we also present concepts of some larger, integrated components such as artificial skin, sensor arrays, and wireless power systems. The common theme of these devices is that they build on an extensive and growing understanding of the parent transistors and diodes, but represent a departure into new physical phenomena and application areas.

This article discusses the importance of the choice of synthetic methodology in the purity, and therefore performance, of both small-molecule and polymeric organic semiconductors. We discuss common methodologies used in the preparation of organic semiconductors, paying particular attention to the impurities and by-products that can arise during these synthetic approaches and how they can have an impact on semiconductor performance.