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Research on organic semiconductor thin films has been accelerated due to their potential for low cost and large area flexible devices. Already there are various products based on organic semiconductor thin films such as displays which have been commercialized. Further studies are needed for the development of flexible devices. In this paper, investigation of various processes for organic semiconductor thin film deposition on flexible substrates and their characterization carried out by us will be reviewed. Two different strategies have been adopted for the fabrication of flexible thin films using conducting polymers as well as molecular semiconductors and they are: (i) synthesis of freestanding films where there is no need for substrates, and (ii) preparation of thin films on flexible substrates. Devices such as organic field effect transistors, memory devices and gas sensors have been demonstrated using various flexible films. The effect of bending on characteristics of films and devices has also been investigated. [ABSTRACT FROM AUTHOR]

We have synthesized two alkenyl (C-6 and C-11 chains) pyrenes and one alkenyl (C-11 chain) perylene as the σ–π systems, which were electro-grafted on H-terminated Si surfaces to form the respective monolayers. The I–V characteristics of the monolayers revealed pronounced rectification in forward bias with a maximum rectification ratio (RR) of 2.5 × 105 at 2.5 V for the C-6-pyrene 4b, 1000 at 1.5 V for the C-11-pyrene 4a and 3000–5000 at 1.75 V for the C-11-perylene 3. The higher RR of the devices containing 4b compared to those of 4a and 3 is possibly due to better alignment and packing of the 4b-monolayers on the Si substrate. The rectification was explained using the ab initio molecular-orbital calculations. [ABSTRACT FROM AUTHOR]