Controlled in situ fabrication of Ag2O/AgO thin films by a dry chemical route at room temperature for hybrid solar cells

Abstract

Silver oxides (Ag₂O and AgO) have attracted increasing attention as potential solar cell materials for photovoltaic devices due to their ideal bandgap and non-toxicity. In order to eliminate the complicated synthesis and harsh reaction conditions (e.g. high temperature, high vacuum, high energy input, electron beam instrumentation) required by most synthetic strategies, we developed a very facile dry chemical approach to directly prepare Ag_xO species on the ITO substrate by taking advantage of a UV-O₃ surrounding in a controlled way. We systematically investigated the effects of relative humidity, reaction temperature, and the silver deposition technique on the formation of silver oxide (AgO or Ag₂O) thin films. A possible synthetic mechanism for the formation of AgO and Ag₂O is proposed. More importantly, we have designed and successfully fabricated novel inorganic hybrid Ag₂O/Bi₂O₃ heterojunction thin films for the first time which exhibit significantly improved photocurrent compared with pure Bi₂O₃ films.