Development of graphene-based sensors on paper substrate for the measurement of pH value of analyte

With excellent properties of graphene material, a number of graphene-based devices have been developed with excellent performance in the past decades. However, difficulty of processing graphene material is a hurdle for its practical realization. In this work, we propose to use vacuum filtration process as the major technique to fabricate graphene-based devices. This technique is simple and effective to practically realize graphene-based sensors on paper substrate, which are equipped with the advantages of low cost, simplicity, flexibility, and disposability. In order to show the functionality of the sensor, determination of pH value of analyte was demonstrated by direct measurement of the resistance across the sensor. Results showed that the sensor has the sensitivity of 30.8 Ω/pH and high linearity (R²=0.9282). Since graphene material can be functionalized by various molecules, it is expected that the graphene-based sensor can be further developed to realize more chemical and biological assays with high sensitivity and specificity for remote environment.