The　dye-sensitized　Zn2SnO4　solar　cells　were　treated　with　Al3+　ions　to　enhance　the　power　conversion　efficiency　for　the　first　time.　Usually,　the　surface　treatment　on　photoanodes　with　Al3+　ions　generated　an　overlayer　of　Al2O3.　For　Zn　2SnO4　photoanode,　another　reaction　pathway　was　found.　The　treatment　with　Al3+　ions　led　to　decreasing　open　circuit　voltage,　and　a　22.6%　enhancement　of　efficiency.　Mott-Schottky　measurements　revealed　that　the　flat　band　of　Zn2SnO4　had　a　positive　shift　owing　to　the　introduction　of　Al3+　ions.　XPS　confirmed　that　Al3+　ions　were　introduced　into　the　lattice　of　Zn2SnO4　and　occupied　the　position　of　Sn4+,　resulting　in　decreased　conduction　band　edge.　TEM　demonstrated　the　size　of　Zn2SnO4　nanoparticles　became　larger　due　to　the　reaction　of　Al3+　with　Zn2SnO　4.　Although　the　adsorption　amounts　of　dyes　lowered　by　21%,　the　driving　force　for　electron　injection　was　greatly　enhanced　as　a　result　of　decreased　conduction　band　edge,　resulting　in　significantly　enhanced　cell　efficiency.　©　2011　Elsevier　Ltd.　All　rights　reserved.