This paper demonstrates a wireless inductor-capacitor (LC) chemical sensor using platinum-doped partially deprotonated-polypyrrole (Pt-PPy+ and PPy0) for real-time and accurate ammonia (NH3) detection. The sensor's impedance is tuned by modulating PPy conductivity, improving return loss (S11). The Pt-PPy+ and PPy0 exhibit p-type semiconductor behavior with strong adsorption-charge transfer dynamics towards NH3, enabling a wide detection range. The sensor discriminates between humidity and NH3 responses (S11 and frequency), allowing self-humidity compensation and accurate NH3 detection. A portable system combining the sensor and a handheld instrument is validated for various applications.

Wen Lv, Jianhua Yang, Qingda Xu, Jaafar Abdul-Aziz Mehrez, Jia Shi, Wenjing Quan, Hanyu Luo, Min Zeng, Nantao Hu, Tao Wang, Hao Wei, Zhi Yang