Humidity sensing behaviour of mono- and dinuclear osmium(IV) chloro complexes

Novel mono- and homodinuclear osmium(IV) chloro complexes of general type [AsPh4][OsCl5(H2O)] (1) and [AsPh4]2[Cl5Os(LL)OsCl5] [LL=pyrazine (2), 4,4′-bipyridine (3)] can be used for the preparation of humidity sensors by thick-film technology. The resistance of the studied samples changes from 109 to 106 W by variation of the relative humidity (RH) from 20 to 95%. Morphological studies using scanning electron microscopy (SEM) are reported. In addition, a possible mechanism of the humidity sensing behaviour is presented.