Enhancing humidity sensing with NiPS3: A theoretical study on selectivity and sensitivity

Humidity sensors are crucial for various applications, including human healthcare, agriculture, storage environments, and the Internet of Things. Historically, sensing materials have struggled with long response and recovery times and small response amplitudes. In this work, we propose and investigate a method for evaluating the relative humidity sensitivity of NiPS₃ using first-principles calculations. Parameters such as adsorption properties, charge transfer, density of states, and I-V relationship were considered. Our findings show that NiPS₃ exhibits enhanced selective sensitivity and rapid response to H₂O compared to other gases, consistent with previous experimental results. NiPS₃ exhibited high current sensitivities of 36.34 % to H₂O at a bias voltage of 0.6 V, with the relative selectivity of H₂O compared with other gases ranging from 6.7 to 17.2. Moreover, theoretical studies on sensor variation with relative humidity indicated that significant physisorption behavior increases conductivity and sensing efficiency under high concentrations of H₂O. Our analysis not only demonstrates the potential of NiPS₃ for humidity sensing applications but also offers a conceptual framework for designing nanomaterial-based humidity sensors, laying a solid theoretical foundation for the further development of efficient humidity sensors.