Comparison of GO/g-C₃N₄ nanocomposite with g-C₃N₄ light-activated humidity sensors at room temperature

Numerous efforts, have been made to achieve higher efficiency in humidity sensors through the use of nanomaterials. Among these, two-dimensional nanomaterials have played a prominent role in enhancing the performance of such sensors. The utilization of various lasers operating at different wavelengths plays a pivotal role in activating humidity-sensing mechanisms, and the synergy between relative humidity (RH) and light irradiation leads to amplified sensing responses in nanomaterials. In the present research, g-C₃N₄ nanosheets and GO/g-C₃N₄ nanocomposite were prepared by sonochemical exfoliation. The physical properties of these 2D nanomaterials were investigated using different characterization techniques. Subsequently, humidity sensors based on these materials were fabricated on Si/SiO₂ substrates. The study compared the humidity sensing capabilities of g-C₃N₄ nanosheets and GO/g-C₃N₄ nanocomposite at dark conditions, as well as when exposed to laser light at different wavelengths. The results indicate that the light-activated humidity sensor made from GO/g-C₃N₄ nanocomposite performs better under 660 nm laser irradiation across different RHs, compared to other wavelengths. Furthermore, under light irradiation, the response and recovery times of the nanocomposite were obtained as 0.5 s and 1 s, respectively, indicating superiority irradiation of nanocomposite under 660 nm wavelength in different RHs of 40% and 80% compared to the dark condition. This pioneering study marks the first empirical validation that the GO/g-C₃N₄ nanocomposite sensor surpasses its pristine g-C₃N₄ counterpart for light-activated humidity-sensing applications.