Beneficial effect of Sn doping on bismuth ferrite nanoparticle-based sensor for enhanced and highly selective detection of trace formaldehyde

Abstract

Pure and sn-doped bismuth ferrite (BFO) nanoparticles were synthesized via facile sol–gel technique. Structural and morphological analysis of the nanoparticles were systematically carried out by using X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, photoluminescence spectroscopy and Brunauer–Emmett–Teller techniques. The gas sensing properties of the sensors based on prepared nanoparticles towards formaldehyde in the temperature range from 200 °C to 400 °C revealed that the doping of Sn enhances the formaldehyde sensing performance of BFO nanoparticle by few folds. Prepared sensors demonstrate p-type behaviour and high selectivity towards formaldehyde. It was observed that the sensor based on 1.5 % Sn doped BFO nanoparticles exhibited maximum sensing response of 3.05 (Rg/Ra) to 1 ppm formaldehyde. Prepared sensors were ultra-fast (response/recovery time of 2.71 s/25.22 s) and very stable having low detection limit of 100 ppb. The enhancement of formaldehyde sensing property due to sn-doping is a combined effect of variation of charge carriers due to valency mismatch and enhanced oxygen defects as confirmed from X-ray photoelectron spectroscopy study. sn-doped BFO nanoparticles could be a potential candidate for the detection of trace formaldehyde gas towards the monitoring of both indoor and outdoor environmental air quality.