Low-temperature, solution-processed organic transistors for flexible electronics

Summary form only given: The materials properties of conjugated small molecule and polymer semiconductors have specific characteristics that make them suitable for applications that cannot easily be addressed by many inorganic materials. Organic semiconductors are inherently low-temperature materials. Due to the absence of covalent bonding between molecules they can be processed at temperatures below typically 100-150°C from either vapour phase or solution into high quality thin films that exhibit a low density of electronic defects. This makes them suitable for applications with a limited temperature window during manufacturing, such as applications that require a flexible plastic substrate, or applications that require integration with other low-temperature materials such as biological molecules. Solution-processible organic semiconductors are compatible with direct-write printing-based manufacturing techniques that have become of interest in order to achieve cost-reductions in large-area electronic applications, such as flat panel displays, and enable new manufacturing paradigms such as roll-to-roll printing, for example for organic solar cells. Among conjugated organic molecules there is an incredible richness in molecular structures which can be tuned to achieve and optimise particular electronic and optoelectronic functions through molecular design. This has been the engine for signif icant improvements in materials and device performance over the years. The efficiency of organic solar cells has increased from levels below 2% 15 years ago to current record levels of 8%. Even more impressive improvements by 3-4 orders of magnitude have been achieved in the field-effect mobility of organic transistors to levels exceeding 1 cm²/Vs. As a result organic semiconductors are now being industrialised for a broad range of applications in displays, electronics, energy and healthcare. In this presentation we will report on recent progress and current st- - atus of organic semiconductor technology with a focus on organic transistors, provide an overview of their materials science and discuss the status of commercialization in flexible displays and other flexible electronic applications.