Rapid and Sensitive Ammonia Gas Sensor using Porous Zinc Oxide Nanoflakes and Cholesteric Liquid Crystals

Hybrid material architectures emerge as a transformative approach to enhance the performance of gas sensors. This study reports a novel room-temperature ammonia (NH₃) sensor based on a porous zinc oxide nanoflakes (ZnOP) and polymer-dispersed cholesteric liquid crystal (PDCLC) composite. The hybrid design integrates the high surface area and mesoporous architecture of ZnO with the functional interfacial properties of PDCLC, yielding a material system that excels in both response and selectivity. The sensor demonstrates exceptional performance metrics, including a broad detection range (1-100 ppm), a low detection limit of 2.61 ppm, and rapid response and recovery times of 5 and 18 s, respectively. Notably, the sensor exhibits superior selectivity toward NH₃ over other volatile organic gases, attributed to the tailored interaction between ammonia molecules and the PDCLC matrix. Moreover, the synergistic interplay between ZnOP and PDCLC enhances electron transfer dynamics, further improving sensing efficiency. This work underscores the potential of porous ZnOP/PDCLC hybrids as advanced materials for ppm-level NH₃ detection and establishes a robust platform for designing high-performance gas sensors operable at room temperature.