Humidity Sensor Based on Rice Husk-Derived Carbon Materials

Abstract

Introduction: Carbon-based materials derived from agricultural waste, such as rice husk (RH), have attracted increasing attention due to their potential for sustainable applications, particularly in electronics, environmental sensing, and energy storage.Objectives: This study aims to investigate the synthesis of carbon materials from RH through thermal decomposition at two different temperatures (900 °C and 1000 °C), and to evaluate their application in humidity sensor fabrication, focusing on the influence of carbonization temperature on their structural and functional properties.Materials and Methods: Carbon materials were synthesized from RH via pyrolysis at 900 °C and 1000 °C. Their structural properties and degree of graphitization were characterized using X-ray diffraction (XRD) and Raman spectroscopy. The resulting materials were then incorporated into conductive inks using different binders and solvents to fabricate resistive humidity sensors. The electrical response of the sensors was evaluated under controlled relative humidity conditions.Results: Structural analyses revealed that higher carbonization temperatures led to more crystalline structures and enhanced graphitization. The fabricated sensors exhibited varying electrical responses depending on the pyrolysis temperature, showing different resistance-relative humidity relationships.Conclusions: Carbonization temperature significantly affects the structural and functional properties of RH-derived carbon materials. These findings highlight the potential of optimizing such materials for environmental sensing applications, particularly humidity monitoring, contributing to the development of sustainable solutions in flexible and printed electronics.