A flexible paper sensor based on polyaniline/germanium film for NH₃ detection

In this paper, we proposed a flexible paper sensor based on nano-sized polyaniline/germanium (PANI/Ge) film to detect ammonia (NH₃) gas. The results indicate that hydrogenated Ge polycrystalline nanomaterial acts as a structure-directing agent, assisting the growth of nanofiber-like PANI. In the sensing experiments, the response of the PANI/Ge sensor is up to 1098.6% (50 ppm NH₃) with the response/recovery time at 72 s/111 s. Moreover, the sensor exhibits good reversibility and selectivity at room temperature. The improvement of sensing performances can be attributed to two aspects: Ge regulates the morphology of PANI, and the rough and porous filter paper as substrate increases specific surface area of the film. It demonstrates that the as-prepared PANI/Ge sensor has a potential application in low-cost disposable devices for NH₃ detection.