Hydrophobic modification of WO3/WS2 heterostructure for construction of humidity immune TEA sensors

In order to achieve Triethylamine (TEA) sensor with high performance, a heterostructure constructed by WS2 and WO3 is designed and synthesized through hydrothermal method and thermal oxidation post-treatment. Via optimization of the oxidation temperature, it is found that the WO3/WS2 hybrid heat-treated at 400 °C, which is predominately composed by WO3 and accompanied with trace WS2, exhibits superior sensing response towards TEA. At its optimum working temperature of 240 °C, the WO3/WS2 sensor shows a sensing response of 21.81–50 ppm TEA. Then polydimethylsiloxane (PDMS) is used for hydrophobic modification to enhance the humidity resistive ability of the sensor. By conformal coating of PDMS layer, the response variation of sensor in the relative humidity (RH) range of 30%∼90% is greatly reduced from 43.43% (WO3/WS2 sensor) to 8.6% (WO3/WS2@PDMS sensor). In addition to the humidity immune property, the WO3/WS2@PDMS sensor demonstrates high response (16.55–50 ppm), superb linearity (R2 = 0.994), high reproducibility, long-term stability and good selectivity to TEA, making it a promising candidate for the construction of TEA sensor in practical application.