Atomically Thin 2D TiO_(2) Nanosheets with Ligand Modified Surface for Ultra-sensitive Humidity Sensor

As a kind of two-dimensional(2D)nanostructured materials,metal oxide nanosheets(MONS)are attractive and promising humidity sensing materials due to their considerable surface area,good charge carrier transportation,and designable surface functional groups properties.Nevertheless,the ultra-thin MONS modified with active functional groups for humidity sensing are still rare.As a proof of concept,the atomically thin TiO_(2)nanosheets with high surface area and electron-donating amino groups are prepared by a structure-maintained post-ligand modification strategy.The fabricated TiO_(2)-based sensors demonstrate superior humidity sensing performance with high response,short response time,narrow hysteresis,and ultra-low theoretical limit of detection of about 15 ppm.Additionally,the possible mechanism is proposed from the AC complex impedance measurements and DC instantaneous reverse polarity experiments.This work provides a possible path for developing the high-performance 2D nanostructured metal oxides-based humidity materials through the surface chemical method.