The　efficiency　of　CdS　quantum　dot-sensitized　Zn　2SnO　4　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　Zn　2SnO　4.　The　efficiency　of　Al　3+　ions-treated　solar　cells　were　improved　by　44%　compared　with　the　untreated　ones.　Polarization　measurements　proved　the　positive　movement　of　the　Zn　2SnO　4　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.