Search

The development of an effective anode material with hierarchical multi-dimensional architecture is conducive to further improve the cell performance of photovoltaic devices. Herein we introduce an intriguing three-dimensional (3D) hierarchically branched hollow sphere-nanowire hybrid TiO2photoanode for promising CdS and CdSe quantum dots co-sensitized solar cells application. The demonstrated 3D hierarchically hybrid photoanode owns a considerably high specific surface area while maintaining roomy space and providing ample porosity for efficient electrolyte infiltration. Moreover, the outstanding light scattering ability of such multi-dimensional architecture leads to an enhancement of light utilization efficiency and thus significantly enhanced short-circuit photocurrent. The control over the pore size of TiO2hollow spheres and the optimizations on the newly developed chemical bath deposited (CBD) cuprous sulfide (Cu2S)/FTO counter electrode eventually yields power conversion efficiency as high as 6.01% for CdS/CdSe based quantum dot-sensitized solar cells (QDSSCs).

The vertically aligned anatase TiO2nanowire arrays with smooth or branched architectures were grown on TCO substrate directly via a simple surfactant-free hydrothermal route. And they were utilized to fabricate efficient quantum-dot sensitized solar cells (QDSSCs) for the first time. The thickness of CdS and CdSe shell were confirmed by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and energy dispersive X-Ray spectroscopy (EDX). A power conversion efficiency of 4.2% was attained with the hierarchical TiO2nanowires based cell, which is 30% higher than that of smooth nanowires devices due to improved short-circuit current density (JSC) and fill factor (FF). The increased JSCprofits from superior light-scattering ability of branched hierarchical TiO2nanowires for enhanced light-harvesting efficiency and the prominent charge-collection efficiency benefited from additional growth of branches for efficient and effective electron injection.