Preparation of Tree-Structured ZnO Films And Application In Quantum Dots Sensitized Solar Cells

Abstract

This study reported the fabrication of tree-structured ZnO films through hydrothermal method. Long ZnO nanowires (NWs) were firstly deposited on the transparent conductive glass substrates. ZnO braches were then grown on the surface of 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. ZnO branches were vertically grown on the ZnO NWs when the concentration of 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. The value of Incident photon-to-current conversion efficiency (IPCE) in the range of 550–650 nm was obviously enhanced with the growth of ZnO braches. The short-circuit current density (JSC) was increased from 9.65 to 12.60 mA cm-2 when the growth time of ZnO branches was 6 h. The overall PCE increased from 3.21% to 5.19%.