| Abstract: | Sintered Bi2O3 pellets exhibited insulating properties at room temperature. Partial reduction of sintered Bi2O3 pellets increased the conductivity. Reduced Bi2O3 pellets exhibited n-type semiconductor properties. Microcrystals of Bi2S3 were formed on sintered Bi2O3 pellets by sulfurizing them in H2S atmosphere. The direct band-gap and indirect band-gap of Bi2S3 were evaluated as 1.2 and 0.4 eV, respectively. A high incident photon to current conversion efficiency in the near IR region was observed on Bi2S3|Bi2O3 electrodes. Photocurrent generation of Bi2S3|Bi2O3 electrodes was explained from the viewpoint of semiconductor sensitization. The flat band potential of Bi2S3 was evaluated as −1.1 V vs. Ag|AgCl in aqueous polysulfide redox electrolyte (1 M OH−, 1 M S2−, 10−2 M S). |
