ZnO Nanorod Humidity Sensor and Dye-Sensitized Solar Cells as a Self-Powered Device

In this paper, ZnO nanorod humidity sensors with dye-sensitized solar cells (DSCs) were prepared on indium tin oxide conductive glass. The average diameter and length of the ZnO nanorods were ~100 nm and ~1.5 μm, respectively. After ZnO nanorods were grown, TiO
₂
film was coated by TiO
₂
with a nanoparticle size of approximately 26 nm through the doctor blade method. The sensitizer N3 was used for charge transfer on the DSCs. The solar photovoltaic conversion efficiency of the DSCs was approximately 4.7%. Humidity sensors were used for measurement under ultraviolet (UV) light at 365 nm. During UV illumination, the current increased under low humidity and gradually decreased under high humidity. The integrated device exhibited similar stable and sensitive performance as the traditional ZnO humidity sensor. Experimental results revealed that DSCs could be integrated with ZnO nanorod humidity sensors to create a self-powered integrated device that has potential Internet of Things applications.