Cu2+-doped ITO as a Novel Efficient, Transparent, and Fast-Response Transducer for Ammonia Sensing

As a novel approach, the effect of Cu2+-doped indium tin oxide (ITO) on a flexible polycarbonate substrate is considered as an ammonia sensor. The sensor was fabricated using spin-coating and subsequent annealing at 160 degrees C for 60min. The constructed sensor morphology accomplished by surface composition was explored using scanning electron microscopy (SEM) and energy dispersiveX-ray (EDX) spectroscopy. Using the new strategy, a flexible sensor for ammonia determination with a fast response time of less than 7 s and a recovery time of 8 s was achieved. Sensor characteristics, such as sensitivity, recyclability, response/recovery time, selectivity, stability, flexibility, and transmittance of the layers, were examined. The impedance results showed high sensitivity when the constructed sensor was exposed to NH3 concentrations in the range 5-1000ppm. The results showed that doping ITO with Cu2+ imparted higher electronic charge density to the sensor surface and enhanced the sensitivity of the sensor by a factor of 352% in comparison with that of pure ITO. The sensitivity, fast response, and recovery time with low-cost materials and deposition procedure suggest an effective and disposable ammonia sensor at room temperature (23 degrees C).