Ion-dipole interaction for selective detection of acetone by perovskite BiFeO₃ chemi-resistive sensor

Present study highlights the ion-dipole interaction mechanism in VOC sensing phenomena of sol-gel synthesized BiFeO₃ chemi-resistive sensor using a set of polar (03) and non/less-polar (03) VOCs. The prototype can selectively detect acetone vapor with a maximum response (R) value of 100 ± 8 at an operating temperature of 350 °C. The sensor shows higher response (R_Ethanol: 62, R_Methanol: 60) towards polar VOCs and low response value (R_Toluene: 12, R_Hexane: 8, R_Xylene: 4) for non/less polar VOCs. The variation of sensor response (R) with the dipole moment (μ) of the VOCs shows excellent linearity. The response time decreases exponentially with increase in dipole moment of VOCs. Acetone with highest dipole moment (μ = 2.91 D) shows lowest response time (τ_res ∼ 20 s). The selective nature of the sensor is correlated with the dipole moment of the target VOCs. Quantitative measure on ion-dipole interactions of polar and non/less-polar VOCs with BiFeO₃ chemi-resistive sensor was evaluated and plays the key role to explain the sensing mechanism. Acetone exhibits highest interaction energy (E_{i- d} = -1.01 × 10^-19 J) among other target vapors, revealing its selective detection by BiFeO₃ chemi-resistive sensor.