Spray-Deposited Rare Earth Metal Ions (La3+ and Sm3+) Substituted CoFe2O4 Thin Films for NH3 Gas-Sensing Applications

We report here the NH3 gas-sensing properties of homemade spray deposited pristine and different concentrations of La3+ and Sm3+ ions substituted CoFe2O4 thin films. XRD findings reveal that the deposited pristine and metal ions substituted CoFe2O4 thin films exhibit the single-phase cubic spinel structure. Also, the calculated average crystallite size was found to decrease from 21 to 17 nm and 21 to 14 nm for La3+ and Sm3+-substituted CoFe2O4 thin films, respectively. AFM topography images show a variation in surface morphology and roughness of CoFe2O4 thin films by the substitution of La3+ and Sm3+ ions in the Fe3+ site, thereby affecting the gas-sensing behavior of CoFe2O4 thin films. Gas-sensing measurement demonstrates that the substitution of La3+ and Sm3+ ions in the CoFe2O4 matrix significantly enhances the gas-sensing characteristics such as sensitivity, gas response, and recovery time of pristine CoFe2O4 thin films. Hence, the experimental results obtained from the present study show that La3+ and Sm3+-ion-substituted CoFe2O4 thin films offer greater potential for the fabrication of room temperature NH3 gas sensors even for low ppm concentrations.

Automated summary

This study reports the NH3 gas-sensing properties of homemade spray deposited CoFe2O4 thin films substituted with La3+ and Sm3+ ions. The results show that the substitution significantly enhances the gas-sensing characteristics of the films, making them potential materials for room temperature NH3 gas sensors even at low ppm concentrations.