A Simple Approach to Fabrication of Highly Efficient Electrolyte-Gated Organic Transistors by Phase Microsegregation of 2,7-Dioctyl [1]benzothieno[3,2-b]benzothiophene and Polystyrene Mixtures

Biorecognition Layer Based On Biotin-Containing [1]Benzothieno[3,2-b][1]benzothiophene Derivative for Biosensing by Electrolyte-Gated Organic Field-Effect Transistors

“…The proposed approach for fabrication of the biorecognition layer in EGOFETs exploits the bilayer structure (Figure ) with receptors anchored to the OSC surface. Recently, we have developed a method for organic electrolytic transistor manufacturing that is based on phase microsegregation in the mixtures of an OSC, C 8 -BTBT-C 8 , and a dielectric polymer, polystyrene (PS) . This mixture in a ratio of 4:1 (C 8 -BTBT-C 8 /PS) was dissolved in toluene with a total concentration of 18 mg/mL and then deposited by a simple easy scalable doctor blading method at a temperature of 75 °C on highly doped silicon substrates pre-heated to 75 °C and containing a 200 nm thick layer of thermally grown silicon dioxide and 35 nm thick gold source and drain electrodes (Figure a).…”

“…The charge transport active layer was obtained by the doctor blading technique using a blend of BTBT and PS in a ratio of 4:1 prepared in toluene at a total concentration of 18 g L −1 . 33 The blend coating was realized under ambient conditions at a blade speed of 1 cm s −1 ; the height of the blade was 650 μm; the temperature of the solution and the substrate was 75 °C.…”

“…First of all, smoothness and high crystallinity degree of the organic semiconducting layer, , as well as excellent electrochemical stability of the organic semiconducting material, are required to achieve stable and reproducible EGOFETs with low threshold voltage and high current values that is necessary for biodetection. The low mobility of polymer chains allows the easy creation of a smooth film based on conjugated polymers: the most widespread polymer used in EGOFET is poly­(3-hexylthiophene) (P3HT) and its derivatives. ,,− However, small molecules, including pentacene and some oligomers such as α-sexithiophene, ,− are also often used for highly crystalline organic semiconducting film fabrication providing high mobility for the charge carriers. ,, Another advantage of the small molecules lies in their higher material purity due to their more controllable molecular structure. One of the most widely used small-molecule OSCs is 2,7-dioctyl[1]­benzothieno­[3,2- b ]­benzothiophene (C 8 -BTBT-C 8 ).…”

“…One of the most widely used small-molecule OSCs is 2,7-dioctyl[1]­benzothieno­[3,2- b ]­benzothiophene (C 8 -BTBT-C 8 ). In spite of the fact that C 8 -BTBT-C 8 has excellent electrochemical stability combined with high mobility of charge carriers, which make it one of the most prominent materials for EGOFETs, ,− application of BTBT-based EGOFETs as biosensors has not been reported yet.…”

“…8,14,25−29 However, small molecules, including pentacene and some oligomers such as α-sexithiophene, 5,30−32 are also often used for highly crystalline organic semiconducting film fabrication providing high mobility for the charge carriers. 5,8,33 Another advantage of the small molecules lies in their higher material purity due to their more controllable molecular structure. One of the most widely used small-molecule OSCs is 2,7-dioctyl [1]benzothieno-[3,2-b]benzothiophene (C 8 -BTBT-C 8 ).…”