Photo-induced negative differential resistance of organic thin film transistors using anthracene derivatives

Abstract

We fabricated organic thin film transistors (OTFTs) using soluble 5,5'-(2,6-Bis((4-hexylphenyl) ethynyl) anthracene-9,10-diyl) bis(ethyne-2,1-diyl) bis(2-hexylthieno[3,2-b] thiophene (HTT-ant-THB) as an active layer. We studied the photo-responsive and the gate field-dependent charge transport characteristics of the HTT-ant-THB-based OTFTs. When light (lambda(ex) = 505 nm) was irradiated on the OTFTs, negative differential resistance (NDR) behavior (i.e., negative slope of the current versus voltage curve) was observed in the reverse bias region of the source-drain current versus voltage characteristics. The NDR effect observed in this study is unique and is controlled by the wavelength and power of the incident light. The current hysteresis and NDR characteristics can be explained in terms of the trapping and releasing mechanism of the mobile charges at the interface between the electrodes and the organic layer. In addition, the NDR effect in the device disappeared on applying negative gate bias. (C)2013 Elsevier B.V. All rights reserved.