Electrical and Optical Characteristics of PQT-12-Based Organic TFTs Fabricated by Floating-Film Transfer Method

Abstract

The electrical and optical characteristics of bottom-gate top-contact poly (3, 3’’’- dialkylquaterthiophene) (PQT-12) polymer-based organic thin film transistors (OTFTs) fabricated by floating-film transfer method (FTM) have been investigated in this paper. The atomic force microscopy, UV-Vis spectroscopy, and photoluminance characteristics of the FTM-based PQT-12 films have been compared with the PQT-12 films deposited by the conventional spin-coating method. The improved electrical characteristics of FTM-based OTFT have been found as compared to those of the spin-coated OTFTs. Due to better properties of the FTM-based PQT-12 films over the spin coated films, the electrical and optical characteristics of the FTM-based OTFT have been compared under dark and illuminated conditions. The FTM film-based OTFT shows the respective values of field effect mobility and threshold voltage of 7.8 × 10−2 cm2/Vs and –8.1 V under dark and 8.9 × 10 −2 cm2/Vs and –5.3 V under illumination of 200 μW/cm2 at 540 nm. The maximum responsivity of 11.3 A/W is found at the light intensity of 5 μW/cm2 at 540 nm.