A highly sensitive ammonia chemical sensor based on α-Fe₂O₃ nanoellipsoids

This paper reports the facile synthesis of α-Fe 2 O 3 nanoellipsoids by a low-temperature hydrothermal process and their effective utilization in the fabrication of a highly sensitive aqueous ammonia chemical sensor by the I – V technique. The as-synthesized α-Fe 2 O 3 nanoellipsoids are characterized in terms of their morphological, structural and optical properties. The detailed structural and optical properties confirm a rhombohedral α-Fe 2 O 3 structure and indirect (1.87 eV) and direct (2.15 eV) band gaps, respectively, for the synthesized nanoellipsoids. The fabricated aqueous ammonia sensor based on nanoellipsoids exhibits a very high and reproducible sensitivity of ∼4.678 µA cm −2 mM −1 and a detection limit of ∼0.04 nM with a correlation coefficient ( R ) of 0.995 in a short response time (10.0 s). The presented work demonstrates that simply synthesized iron oxide nanostructures can efficiently be used for the fabrication of reliable and reproducible chemical sensors.