Effect of graphene weight percentage on surface morphology and humidity-sensing performances of hydroxyapatite/graphene nanocomposite

Graphene-based nanocomposites have gained significant attention due to their excellent mechanical, electrical, thermal, optical, and chemical properties. This work synthesizes hydroxyapatite (HAp) nanocomposite for humidity-sensing applications with varying weight percentages of graphene nanoplatelets (GNP). The structural and surface morphology of the composite sensor were analyzed using X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). The humidity-sensing properties of composite such as sensitivity response and recovery were studied. The humidity-sensing behaviour of the nanostructured composite was investigated in the range of 10% to 99% relative humidity. The amount of GNP also influences the HAp-GNP composite’s sensing capabilities added in HAp. In addition, the humidity-sensing results show that adding 0.5 wt % GNP to HAp enhanced sensitivity more than three times over pure HAp was used. Compared to pure hydroxyapatite, which has a maximum sensitivity of 5320%, this composite sensor has a substantially higher sensitivity of 18,680%. The HAp-GNP composite’s sensitivity results show that it has the potential to be used in ultra-high performance humidity sensors.