A high-performance resistive humidity sensor based on Nb₂CT_x/MoS₂ heterojunction for non-contact sensing

A Nb₂CT_x/MoS₂ humidity sensor with high sensitivity, low hysteresis, and fast response/recovery for non-contact sensing was prepared. The built-in electric field formed at Nb₂CT_x/MoS₂ heterojunction interface promotes water molecule adsorption and increases the interfacial potential barrier, thus significantly enhancing the response. Meanwhile, the composite possesses a larger specific surface area and abundant hydrophilic functional groups, which provide sufficient active adsorption sites for water molecules and accelerate interfacial electron transfer, reducing response/recovery time and humidity hysteresis of the device. Electrical measurements reveal that within 11-95% RH, the sensor exhibits an ultrahigh sensitivity of 238085 Ω/%RH, a fast response/recovery time of 20.1/4.4 s, and low humidity hysteresis of 5.23%. First-principles calculations confirm that the adsorption energy of water molecules on the heterojunction is about 21 times that on MoS₂, providing theoretical support for its superior sensing performance. The sensor enables non-contact detection of human respiration and fingertip distance, offering a feasible strategy for the design of high-performance humidity-sensitive materials.