The　efficiency　of　CdS　quantum　dot-sensitized　Zn2SnO4　solar　cells　(QDSSCs)　was　improved　by　a　novel　surface　treatment　with　Al　3+　ions.　The　driving　force　for　electron　injection　was　strengthened　for　QDSSCs　owing　to　the　reduced　conduction　band　edge　of　Zn2SnO　4.　The　efficiency　of　Al3+　ions-treated　solar　cells　were　improved　by　44%　compared　with　the　untreated　ones.　Polarization　measurements　proved　the　positive　movement　of　the　Zn2SnO4　conduction　band　edge.　Although　the　deposited　amounts　of　CdS　QDs　decreased　after　the　surface　treatment,　the　electron　lifetimes　were　prolonged　and　the　interfacial　charge　recombination　was　inhibited,　giving　rise　to　a　greatly　improved　short-circuit　current　and　efficiency.　By　optimizing　the　number　of　cycles　of　chemical　bath　deposition,　a　maximum　efficiency　of　0.263%　was　achieved　under　the　illumination　of　one　sun　(AM1.5,　100　mW　cm-2).　©　2011　Elsevier　Ltd.　All　rights　reserved.