Humidity-dependent electrical conductivity of Na_(0.33)K_(0.02)(H_2O)_(1.33)CoO_(1.95) and Na_(0.07)K_(0.21)(H_2O)_(0.63)CoO_(1.80)

摘要

We report studies of cobalt oxyhydrates Na_x(H_2O)_yCoO_2 as potential humidity sensor. All the samples are of single phase with hexagonal structure. Direct-current conductivity measurements as a function of humidity are carried out using four-probe sensing techniques. Na_(0.33)K_(0.02)(H_2O)_(1.33)CoO_(1.95) and Na_(0.07)K_(0.21)(H_2O)_(0.63)CoO_(1.80) can absorb and desorb water molecules reversibly. Our earlier studies on cobalt oxyhydrates reveal that these materials can be candidate materials for moisture detection with a wide range of linearity.