Wide-range and high-accuracy wireless sensor with self-humidity compensation for real-time ammonia monitoring

Real-time and accurate biomarker detection is highly desired in point-of-care diagnosis, food freshness monitoring, and hazardous leakage warning. However, achieving such an objective with existing technologies is still challenging. Herein, we demonstrate a wireless inductor-capacitor (LC) chemical sensor based on platinum-doped partially deprotonated-polypyrrole (Pt-PPy + and PPy 0 ) for real-time and accurate ammonia (NH 3 ) detection. With the chemically wide-range tunability of PPy in conductivity to modulate the impedance, the LC sensor exhibits an up-to-180% improvement in return loss ( S11 ). The Pt-PPy + and PPy 0 shows the p-type semiconductor nature with greatly-manifested adsorption-charge transfer dynamics toward NH 3 , leading to an unprecedented NH 3 sensing range. The S11 and frequency of the Pt-PPy + and PPy 0 -based sensor exhibit discriminative response behaviors to humidity and NH 3 , enabling the without-external-calibration compensation and accurate NH 3 detection. A portable system combining the proposed wireless chemical sensor and a handheld instrument is validated, which aids in rationalizing strategies for individuals toward various scenarios.