Rapid‐Response Humidity Sensor Enabled by Silver Nanowire‐Decorated Tin Dioxide Nanostructures

This study successfully synthesized silver nanowire‐modified tin dioxide (SnO 2 /Ag) composites via a hydrothermal method for high‐performance resistive humidity sensing. By systematically adjusting the Ag/Sn molar ratios (1%, 3%, and 5%), the effects of silver nanowires on the crystal structure, surface chemistry, and humidity‐sensing properties of SnO 2 were comprehensively investigated. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) analyses revealed that Ag nanowires (AgNWs) effectively inhibited SnO 2 grain growth and generated abundant oxygen vacancies and surface hydroxyl groups, thereby enhancing moisture adsorption capability. X‐ray photoelectron spectroscopy (XPS) results further confirmed electron transfer between SnO 2 and Ag, indicating the formation of a heterojunction interface. Regarding sensing performance, the SnO 2 /Ag‐3 composite exhibited the best overall characteristics, including a sensitivity of 1339.8, response and recovery times of 9 and 5 s, respectively, a hysteresis error of 1.13%, and excellent long‐term stability and selectivity during a 30‐day test cycle. Mechanistic analysis suggests that AgNWs not only provide efficient electron‐transport pathways but also facilitate rapid water desorption through Joule heating. This work presents an effective material design strategy for developing highly sensitive and fast‐response humidity sensors.