Topographic substrates as strain relief features in stretchable organic thin film transistors

The fabrication of large-area active devices that can operate under large tensile strains is essential for advancing the technological applications of flexible and stretchable electronics. Here we describe a strain relief mechanism to preserve the performance of organic thin film transistors that operate under strains up to 12%. The scalable fabrication strategy utilizes sinusoidal topographic structures that are directly integrated into elastomeric substrates through controlled buckling. Organic thin film transistors are then prepared onto the prefabricated topographic substrates by conformal coating methods. The stretchability of devices fabricated on substrates with strain relief features is demonstrated by characterizing the strain-dependent performance of transistors in multiple deformation configurations. Devices fabricated on topographic substrates exhibit stabilized operation as measured by maintaining high mobilities and on-off ratios compared to the devices fabricated on flat substrates without strain relief features. The overall utility of topographic substrates is derived from the ability to embed intrinsic stretchability into arrays of active devices in large-area formats in a highly scalable manner. (C) 2013 Elsevier B.V. All rights reserved.