Agradecimentos: This work was supported by the Qatar National Research Fund (project number UREP 25-057-2-023). The statements made herein are solely the responsibility of the authors. The characterizations of this work were accomplished in the Central Laboratories Unit, Qatar University. All authors have read and agreed to the published version of the manuscript. Authors acknowledges CAPES (Coordination for the Improvement of Higher Education Personnel) under the Brazilian Ministry of Education for the financial support in the form of a graduate fellowship. STEM experiments are conducted as part of a user proposal at the Center of Nanophase Materials Sciences, which is a DOE Office of Science User Facility. This work also thank the Brazilian agencies São Paulo Research Foundation (FAPESP) (grant 2023/08122-0) and CNPq – National Council for Scientific and Technological Development – Brazil (process 304957/2023-2) for financial support and the Center for Scientific Computing (NCC/GridUNESP) of São Paulo State University (UNESP) for computational support Ver menos

Abstract: 2D materials-based planar devices have been sought after for gas and humidity sensor applications owing to their high sensitivity due to their ultrathin nature and increased surface area. Herein, 2D WSe2 films-based planner devices were fabricated to evaluate their performance for potential application in humidity sensors. The structure and morphology of the WSe2 sensing films were studied by Raman spectroscopy, photoluminescence, optical microscopy, and scanning electron microscopy (SEM) techniques. The relative humidity-dependent sensing performances of the 2D WSe2 films were evaluated using current-voltage (I-V), relative impedance, and complex total impedance (electrochemical impedance spectroscopy, EIS) techniques. This sensor showed a very stable and repeatable performance investigated over the period of 18 months. The response and recovery times of the WSe2-based impedance sensors were found to be 40 and 30 s, respectively. The WSe2 sensor exhibits a 2 +/- 1% minimum hysteresis at a lower humidity level (50% RH) and around 8 +/- 2% maximum hysteresis at relative humidity level (70% RH). This value of hysteresis is in the acceptable range during the initial investigation of any material to explore its potential for application in humidity sensors. The density functional theory (DFT) analysis was performed with the interaction from water molecules of the WSe2 sample for a better understanding of the sensing mechanism of devices Ver menos