Highly sensitive resistive humidity sensor based on strontium-doped lanthanum ferrite nanofibers

Humidity sensors are the most widely applied sensors. Although some highly sensitive humidity sensors have been explored, devices that can accurately detect low humidity are still required. Improving the adsorption of water molecules by surface regulation is an effective way to enhance humidity sensitivity. In this study, electrospinning prepared a series of lanthanum ferrite samples doped with different concentrations of strontium. For the sample with a surface atomic ratio between strontium and lanthanum was approximately 0.2, there was a 6 x 104 times change in the resistance of the sensor to 90% relative humidity, and the response was 6.76 for 4% relative humidity. Negligible hysteresis, and excellent stability demonstrate the advantages of the strontiumdoped lanthanum ferrite nanofibers. The sensing mechanism was discussed by measuring the change of band gap and work function of samples with different concentrations of strontium doping. Furthermore, suitable doping also decreased the adsorption energy and increased the charge transfer during the adsorption of water molecules on the surface of lanthanum ferrite based on the calculations. This study provides a new perspective for enhancing the sensitivity of humidity sensors via surface regulation.

Automated summary

In this study, lanthanum ferrite samples doped with different concentrations of strontium were prepared using electrospinning. The sample with a surface atomic ratio of approximately 0.2 showed a 6 x 104 times change in resistance at 90% relative humidity, and a response of 6.76 at 4% relative humidity. Suitable strontium doping decreased the adsorption energy and increased the charge transfer during water molecule adsorption on the surface of lanthanum ferrite. This study offers a new perspective for enhancing humidity sensor sensitivity through surface regulation.