LAUSR

Abstract In this work, we present the fabrication of tree-structured-based ZnO films by applying the hydrothermal method. For that reason, ZnO nanowires (NWs) with extended lengths were initially deposited on transparent conductive glass substrates, while ZnO branches were subsequently grown on the surface of the ZnO NWs. The morphology of the as-prepared tree-structured ZnO films was affected by several factors, such as the concentration of Zn(CH3COO)2 in the seed precursor solution and the hydrothermal reaction time. In addition, ZnO branches were vertically grown on the ZnO NWs when the concentration of the Zn(CH3COO)2 was 0.04 M. Quantum dots (QDs)-sensitized solar cells were assembled using the CdS/CdSe QDs co-sensitized ZnO films as the photoanodes. From our results, it is demonstrated that the value of the incident photon-to-current conversion efficiency (IPCE) in the range of 550–650 nm was obviously enhanced with the growth of ZnO branches, rendering our approach attractive for the development of energy-efficient solar cells.