Flexible spray-coated TIPS-pentacene organic thin-film transistors as ammonia gas sensors

Xinge Yu, Nanjia Zhou, Shijiao Han, Hui Lin, Donald B. Buchholz, Junsheng Yu, Robert P. H. Chang, Tobin J. Marks, Antonio Facchetti
2013 Journal of Materials Chemistry C  
The OTFTs were fabricated according to the following procedure. The indium tin oxide (ITO) coated glass and ZITO coated AryLite polyester were used as the substrates and the gate electrodes. The ITO coated glass was purchased from commercial sources (Thin Film Devices Inc.), and the amorphous ZITO film having 250 nm thickness was deposited on flexible substrates, AryLite polyester, by pulsed laser deposition (PLD). Here 30% of the ITO In is replaced by Zn and Sn (Zn0.3In1.4Sn0.3O3). The
more » ... 0.3O3). The transparency of the ZITO/AryLite polyester substrates is >80 %, the sheet resistance of the ZITO films <20 Ω/□, and the mechanical flexibility of these ZITO/AryLite polyester substrates shows an bending radius ~2.5 mm. PMMA (Aldrich, MW~350,000) was selected as the dielectric layer, was dissolved in chlorobenzene to form a 7 % solution after stirring for more than 10 h by stir bar. Then PMMA solution was next spin-coated on ITO/glass and ZITO/AryLite as the dielectric layer, and baked on a hot plate at 150 °C for 1 h. Using a Veeco Dektak 150 surface profiler, the thickness of PMMA film was measured to be ~ 520 nm. Subsequently, Various concentrations of TIPS-pentacene solution, from 2 to 8 mg/mL, were prepared in dichlorobenzene, and deposited via spray coating on the PMMA dielectric layer as the OTFT active layers. After extensive optimization, optimal films were obtained by controlling the spray coating parameters as such the height from the nozzle tip-to-substrate at 15 cm, with a spray pressure of 40 psi using Electronic Supplementary Material (ESI) for Journal of Materials Chemistry C This journal is
doi:10.1039/c3tc31412j fatcat:kdrq6peqa5gkxj3x47e6ad5rtm