Water-stable organic transistors and their application in chemical and biological sensors

TLDR

Low‑cost, reliable sensors require devices that translate analyte binding into an easily read electrical signal, and organic thin‑film transistors (OTFTs) are ideal for inexpensive, single‑use chemical or biological sensors because they are compatible with flexible, large‑area substrates, simple processing, and highly tunable active layers. We fabricated low‑operating‑voltage OTFTs with a cross‑linked polymer gate dielectric that remain stably operational for over 10 000 electrical cycles in aqueous environments, using the p‑channel semiconductor 5,5′‑bis‑(7‑dodecyl‑9H‑fluoren‑2‑yl)‑2,2′‑bithiophene (DDFTTF). The OTFT sensors achieved parts‑per‑billion sensitivity for trinitrobenzene, methylphosphonic acid, cysteine, and glucose in aqueous solutions, demonstrating reliable operation in water and opening new possibilities for chemical and biological sensing with OTFTs.

Abstract

The development of low-cost, reliable sensors will rely on devices capable of converting an analyte binding event to an easily read electrical signal. Organic thin-film transistors (OTFTs) are ideal for inexpensive, single-use chemical or biological sensors because of their compatibility with flexible, large-area substrates, simple processing, and highly tunable active layer materials. We have fabricated low-operating voltage OTFTs with a cross-linked polymer gate dielectric, which display stable operation under aqueous conditions over >10 4 electrical cycles using the p-channel semiconductor 5,5′-bis-(7-dodecyl-9H-fluoren-2-yl)-2,2′-bithiophene (DDFTTF). OTFT sensors were demonstrated in aqueous solutions with concentrations as low as parts per billion for trinitrobenzene, methylphosphonic acid, cysteine, and glucose. This work demonstrates of reliable OTFT operation in aqueous media, hence opening new possibilities of chemical and biological sensing with OTFTs.