Researchers have managed to create a highly stretchable organic semiconductor by blending high mobility semiconducting polymers with an elastomer.
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Background: Stanford researchers have created a highly stretchable organic semiconductor by blending high mobility semiconducting polymers with an elastomer. The CONPHINE (conjugated polymer/elastomer phase separation induced elasticity) semiconducting film can be stretched up to 100% strain without affecting mobility, retaining values of 1 cm2 V-1s-1, comparable to that of amorphous silicon. The charge carrier mobility of these durable films are maintained even after 100 times stretching cycles under 100% strain - making CONPHINE films excellent candidates for wearable technology, biocompatible devices, and electronic skins for robotics or prostheses. 3D morphology of the polymer semiconductor - The increased polymer chain dynamics under nanoconfinement reduces the modulus of the conjugated polymer and delays the onset of crack formation under strain, without affecting charge mobility. Stage of Research: Scientists have fabricated stretchable thin film transistors using the CONPHINE method. The fully stretchable transistors exhibit high stretchability with minimal change in drain current even when poked with a sharp object. CONPHINE TFT drain current under stretching, twisting, and even poking by a sharp object. The robust device maintained performance over 1000 repeated stretching cycles to 25% strain at four cycles per second (the general range for applied strains in most wearable electronic applications). Researchers also tested a skin-like finger wearable driver for a light-emitting diode to demonstrate potential use for wearable electronics. Applications: Stretchable semiconductor devices for: Wearable and mobile platforms Biocompatible devices and health monitoring Electronic skins for robotics and prostheses Advantages: Excellent electronic performance under stretching: Charge carrier mobility values same or slightly higher compared to that of a neat conjugated polymer thin film. Durable - At high strains up to 100%, the mobility values of blending films do not decrease and are maintained around 1 cm2 V-1s-1 (3x the neat conjugate polymer and 100% better than any average mobility previously reported for organic semiconductors under high strain).