Abstract
► Well-crystalline ZnO nanopencils were synthesized by very simple and facile hydrothermal process using simply available laboratory chemicals. ► Using ZnO nanopencils, a liquid ammonia chemical sensor is fabricated based on convenient and simple current–voltage (I–V) principle. ► The fabricated liquid ammonia chemical sensor exhibits the highest sensitivity ever reported in the literature. ► The obtained detection limit of the fabricated sensor is lower than the previously reported literature values.
This paper reports a very simple, reliable and facile methodology to fabricate ultra-high sensitive liquid ammonia chemical sensor using well-crystalline hexagonal-shaped ZnO nanopencils as an efficient electron mediator. A low-temperature facile hydrothermal technique was used to synthesize ZnO nanopencils. The synthesized nanopencils were characterized in detail in terms of their morphological, structural and optical properties which confirmed that the synthesized nanomaterial is well-crystalline, possessing wurtzite hexagonal phase and possess very good optical properties. A very high sensitivity of ∼26.58μAcm−2mM−1 and detection limit of ∼5nM with a correlation coefficient (R) of 0.9965 and a response time of less than 10s were observed for the fabricated liquid ammonia by I–V technique. To the best of our knowledge, by comparing the literature, it is confirmed that the fabricated sensor based on ZnO nanopencils exhibits highest sensitivity and lowest detection limit for liquid ammonia. This research opens a way that simply synthesized nanomaterials could be used as efficient electron mediators for the fabrication of efficient liquid ammonia chemical sensors.