Enhanced Humidity Sensing Performance of the La<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub>/La(OH)<sub>3</sub> Nanocomposite
Jingsong Wang, Li Li, Gaifang Chen, Chunchang Wang
Abstract
A La2Ti2O7/La(OH)3 nanocomposite was prepared by the one-step hydrothermal method. Humidity sensing properties of this material were investigated based on the impedance-type sensor in the relative humidity range of 11–94%. This material in the tested humidity range shows a large impedance change of more than four orders of magnitude. This impedance change is one order larger than that of the sensors based on La2Ti2O7 and La(OH)3. Excitingly, the impedance has an excellent linear relationship with humidity with a figure of merit R2 = 0.995. The enhanced humidity properties of the La2Ti2O7/La(OH)3-based sensor are argued to be due to the existence of a heterojunction between La2Ti2O7 and La(OH)3. The excellent linearity was argued to be due to the synergetic effect of the heterojunction and Grotthuss mechanism.