Experimental investigation of performance tailoring of the multifunctional sensor using transition metal (Fe) doped ZnO nanorods synthesized via a facile solution-based method

A systematic interpretation of the undoped and Fe doped ZnO based multifunctional sensor developed employing economic and facile low-temperature hydrothermal method is reported. The tailoring of the performance improvement of the sensor was deliberately carried out using varied concentration (1, 3 and 5 Wt%) of Fe dopant in ZnO nanorods. The structural and morphological analysis reveal the undisturbed ZnO hexagonal wurtzite structure formation and 1D morphology grown even when the dopant is added. The optical property study evidences a decreased bandgap (3.10 eV) and decreased defects of 5 Wt% of Fe dopant in ZnO nanorods based sensor compared to the undoped one. The electrical process transpiring in the tailored multifunctional sensor is investigated using photoconductivity and impedance analysis elucidates proper construction of p-n junction between the piezoelectric n-type active layer (undoped and Fe doped ZnO nanorods) and p-type PEDOT:PSS ((poly(3,4-ethylene dioxythiophene) polystyrene sulfonate)) and reduced internal resistance of 5 Wt% of Fe dopant in ZnO nanorods based sensor (131.97 Ω) respectively. The investigation on the experimental piezoelectric acceleration and gas sensing validation and the performance measurement were interpreted using test systems. A revamped output voltage of 3.71 V for 1 g input acceleration and a comprehensive sensitivity of 7.17 V g^-1was achieved for the 5 Wt% of Fe dopant in ZnO nanorods based sensor sensor. Similarly, an upgraded sensitivity of 2.04 and 6.75 for 5 Wt% of Fe dopant in ZnO nanorods based sensor was obtained when exposed to 10 ppm of target gases namely CO and CH₄respectively at room temperature. Appending to this, acceptable stability of the sensor for both the sensing (acceleration and gas) was also attained manifesting its prospective application in multifunctional based systems like sewage systems.