Stable and Scalable Electrolyte-Gated Organic Thin-Film Transistors for Biosensing

Electrolyte-gated organic field-effect transistors (EGOFETs) are ideal for biosensing, as they operate at low voltages and directly transduce changes in aqueous biological media. In this work, we characterize dinaphtho[2,3-b:2',3'-<i>f</i>]thieno[3,2-<i>b</i>]thiophene (DNTT) and C₁₀-DNTT EGOFETs in a phosphate-buffered saline (PBS) solution, demonstrating an intrinsic mobility of at least 2.8 ± 0.4 × 10^-2 cm²/(V s), and a contact resistance of 3.1 ± 0.1 kΩ-cm. Transistors are scaled to channel lengths as small as 2 μm, and scaling effects, such as mobility degradation, threshold voltage roll-off, and drain-induced barrier lowering (DIBL) are characterized. While contact resistance and DIBL both affect the performance of scaled EGOFETs, the concomitant increase in transconductance and transit frequency ensures that scaling is a path to high performance. Proteins and induced pluripotent stem-cell cardiomyocytes are applied to 2 μm C₁₀-DNTT transistors that maintain their performance after 1 week of incubation. C₁₀-DNTT EGOFETs therefore may be scalable, high-performance, and stable candidates for biosensing applications.