ABSTRACT Ammonia (NH 3 ) is a toxic gas that must be detected at low concentrations at room temperature. This study synthesized a polyaniline/zinc oxide (PANI/ZnO) composite via an in situ polymerization method, using ZnO prepared via green synthesis from pineapple peel waste. The composite was then applied to a printed circuit board (PCB) substrate with interdigitation electrodes and characterized using XRD, FTIR, and SEM‐EDX. The sensor test results showed that PANI/ZnO with 0.3 g ZnO added provided the highest sensitivity of 79% at 4 ppm NH 3 , higher than that of pure PANI (61%). The sensor also showed a fast response time (20–29 s), a recovery time of 61–79 s, and good stability in repeated tests. This performance improvement resulted from the synergistic effect of the p–n heterojunction between PANI (p‐type) and ZnO (n‐type). This study confirms that the environmentally friendly PANI/ZnO composite has excellent potential to be developed as a low‐concentration NH 3 sensor at room temperature with sustainable and cost‐effective application prospects.
Putri et al. (Sun,) studied this question.