Solution-processed all-oxide nanostructures for heterojunction solar cellsElectronic supplementary information (ESI) available: The experimental section including fabrication procedures, details of ITO substrate, Cu2O and Sn1−xCoxO2 powders preparation. See DOI: 10.1039/c1jm13303a

A low-cost, non-toxic, environmentally friendly, and solution-processed new oxide-based semiconducting material (Sn 1− x Co x O 2 ) was developed as an absorption material for all oxide solar cell fabrication in this work. The newly developed n-type cobalt-doped tin oxide (n-Sn 1− x Co x O 2 ) nanoparticles and p-type copper oxide (p-Cu 2 O) nanostructures were successfully synthesized via a low-temperature solution process. Combined with the use of non-vacuum spray and hot-press processes, the n-Sn 1− x Co x O 2 /p-Cu 2 O heterojunction solar cells exhibit low-cost and large-scale fabrication advantages. The highest power conversion efficiency (PCE) of 1.2% can be obtained from the solar cells with n-Sn 0.86 Co 0.14 O 2 /p-Cu 2 O, under AM 1.5 illumination, a noteworthy improvement in solution-processed all-oxide-based nanostructures heterojunction solar cells. A solution-processed n-Sn 0.86 Co 0.14 O 2 /p-Cu 2 O nanostructures heterojunction solar cell with a power conversion efficiency of 1.2% was fabricated.