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Electronic devices that can interface with the human body are highly desirable for sensing of physiological parameters and for smart prosthetics. This is particularly challenging since the mechanism of signalling in most electronic materials is different from the mechanism of signalling in the human body. Most electronic devices in our daily life send signals through flow of electrons while body signals are carried via the exchange of ions and protons. There is a considerable interest in developing bioinspired proton conducting materials and solid-state devices for bio-electronic applications [1, 2, 3].
In this work, we will present a new class of proton conducting gate materials, sulphonated mesoporous silica nanoparticles (SMSN) [4], that are able to sense conduction of protons in all solid state, low voltage operating organic thin film transistors (OTFTs). Ordered mesoporous silica nanoparticles with various functional groups have been investigated for applications in catalysis, gas adsorption and drug delivery. SMSN have also been successfully investigated for applications in fuel cell membranes [4]. In this presentation, we will describe the OTFT operation of solution processable SO3H-MCM-41 films that have highly ordered pore structures. The OTFTs fabricated maintained low voltage transistor output characteristics for operating source-drain voltages 0 > Vds > -1.25 V.
We will also present results that demonstrate the application of our low voltage operating OTFTs in sensing proton exchange, where a drop of H2O2 dropped on top of the SO3H-MCM-41 gate electrode captures strong modulation in the current flow. H2O2 breaks down to oxygen, protons and electrons when a voltage above a threshold voltage is applied between source and drain. The Ids increases immediately by ~ 3-fold and continues to increase to a maximum value of ~ 5-fold, demonstrating that these OTFTs are highly applicable in advanced biomedical sensing applications.
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2. C.J. Wan, L.Q. Zhu, Y. H. Liu, P. Feng, Z.P. Liu, H.L. Cao, P. Xiao, Y. Shi, Q. Wan, Adv. Mater. 28, 3557-3563 (2016).
3. C. Zhong, Y. Deng, A.F. Roudsari, A. Kapetanovic, M.P. Anantram, M. Rolandi, Nature Comm. 2, 476 (2011).
4. R. Marschall, I. Bannat, A. Feldhoff, L. Wang, G.Q. Lu, M. Wark, Small 5 (7), 854-859 (2009).
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