Cellulosic graphene: growth, characterization, and fabrication toward ambient humidity sensing

Monitoring environmental humidity using a sensitive, cost-effective device is a contemporary challenge. Considering various sensing materials, graphene has functioned as a best-suitable material for humidity sensing because of its favorable characteristics, for example, large reactive surface area (highly sensitive), better electrical conductivity (fast response of water adsorption), etc. A straightforward and bio-acceptable approach to growing multilayer graphene was formed by the thermal exfoliation process of cellulosic materials. The crystallite size, inter-layer distance, number of layers, crystalline defects, and crystalline planes orientation for synthesized cellulosic-graphene materials were characterized from X-ray diffraction (XRD) analysis, Raman spectroscopy, and High-resolution transmission electron microscopy (HRTEM). Additionally, the elemental analysis was provided by Energy-dispersive X-ray (EDX) spectroscopy. A market-ready product on humidity sensor was fabricated and studied the different parameters associated with sensing mechanism, for example, hysteresis effect with different temperature, effect on impedance with relative humidity, sensitivity, etc. The fabricated device's better response time and stability may be observed with commercially available humidity sensors (HIH5030 and DHT11H).

Automated summary

A sensitive and cost-effective humidity sensor was fabricated using multilayer graphene synthesized through thermal exfoliation of cellulosic materials. The device showed better response time and stability compared to commercially available humidity sensors.