P-type CoO nanowire arrays and their application in quantum dot-sensitized solar cells

P-type cobalt oxide (CoO) nanowire arrays were synthesized via a hydrothermal process followed by thermal annealing. Then, n-type CdS nanoparticles were electrodeposited onto the CoO nanowires to obtain CdS/CoO nano-heterojunctions. The heterojunctions were utilized as the photocathode of solar cells, which show promising photoelectrical properties, particularly rather high photocurrents, due to efficient light absorption and improved carrier collection. This study demonstrates that the p-type CoO nanowire is an attractive candidate material for photovoltaic applications, and the hydrothermal synthesis combined with the electrodeposition process is a potential technique for producing low-cost solar cells.