Dual-biased metal oxide electrolyte-gated thin-film transistors for enhanced protonation in complex biofluids
Year: 2024
Type: article
Abstract: pH sensing technology is pivotal for monitoring aquatic ecosystems and diagnosing human health conditions. Indium-gallium-zinc oxide electrolyte-gated thin-film transistors (IGZO EGTFTs) are highly regarded as ion-sensing devices due to the pH-dependent surface chemistry of their sensing membranes. However, applying EGTFT-based pH sensors in complex biofluids containing diverse charged species poses challenges due to ion interference and inherently low sensitivity constrained by the Nernst limit. Here, we propose a dual-biased (DB) EGTFT pH sensing platform, acquiring back-gate-assisted sensitivity enhancement and recyclable redox-coupled protonation at the semiconductor-biofluid interface. A solution-processed amorphous IGZO film, used as the proton-sensitive membrane, ensures scalable uniformity across a 6-inch wafer. These devices demonstrate exceptional pH resistivity over several hours when submerged in solutions with pH levels of 4 and 8. In-depth electrochemical investigations reveal that back-gate bias significantly enhances sensitivity beyond the Nernst limit, reaching 85 mV/pH. This improvement is due to additional charge accumulation in the channel, which expands the sensing window. As a proof of concept, we observe consistent variations in threshold voltage during repeated pH cycles, not only in standard solutions but also in physiological electrolytes such as phosphate-buffered saline (PBS) and artificial urine, confirming the potential for reliable operation in complex biological environments.
Source: Scientific Reports
Institution: Ajou University
Language: English
Subfield: Bioengineering
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,590
Funders: National Research Foundation, Ministry of Trade, Industry and Energy, Korea Institute for Advancement of Technology, Korea Basic Science Institute, National Research Foundation of Korea, Ministry of Education, India, Iran Telecommunication Research Center, Ministry of Science and ICT, South Korea, Commercializations Promotion Agency for R and D Outcomes, Institute for Information and Communications Technology Promotion
OpenAlex ID: W4405842593