Surface photocurrent gas sensor with properties dependent on Ru(dcbpy)_2(NCS)_2-sensitized ZnO nanoparticles

摘要

An original photoelectric gas sensor, fabricated by Ru(dcbpy)_2(NCS)_2 (dcbpy = 2,2′-bipyridyl-4,4′-dicarboxylate)(RuN3)-sensitized ZnO on a comb-like electrode by surface photocurrent technique with excitation of visible light (545 nm), is presented for CO and O_2 detection at room temperature. The surface photocurrent (I_(SPC)) of a sample can be dramatically enhanced and diminished depending on the properties of the gases. As a reductive gas, CO can make I_(SPC) increase and the sensor response is linear to the change in CO concentration with a detection limit of 0.62 Torr. However, I_(SPC) decreases upon O_2 adsorption, since it can capture electrons from the surface. There is no linear dependency between I_(SPC) and concentration of O_2. In this article a microscopic mechanism of the photoelectric gas sensor has also been discussed in detail. This research should be valuable for the practical application of the ZnO gas sensor.