Bottom-contact organic field-effect transistors based on single-crystalline domains of 6,13-bis(triisopropylsilylethynyl) pentacene prepared by electrostatic spray deposition

• Large crystalline domains of TIPS pentacene were prepared by ESD.
• We fabricated BC-OFETs based on single-crystalline domains of TIPS pentacene.
• The devices exhibited high mobilities, but resulted in high threshold voltages.
• The threshold voltage could be lowered by reducing the thickness of BC electrodes.

Large crystalline domains (a few hundred micrometers in size) of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) were prepared by electrostatic spray deposition (ESD) and used as the active layers of bottom-contact organic field-effect transistors. The TIPS pentacene active layers were directly patterned via a shadow mask in the ESD process. The device, which had a 5-μm-long channel composed of a single-crystalline domain, exhibited a high field-effect mobility of more than 0.1 cm2/V s but resulted in a high threshold voltage of −17 V. The threshold voltage could be lowered to −6.4 V by reducing the thickness of the BC electrodes from 30 to 10 nm; this threshold voltage lowering was probably due to an improvement in the charge injection from the source electrode to the active layer.

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