Three-dimensional hyperbranched TiO2/ZnO heterostructured arrays for efficient quantum dot-sensitized solar cells

Abstract

The ingenious design of nanostructures and smart integration of specific semiconducting metal oxide materials are closely related to the photovoltaic performance of solar cells. Herein, we successfully fabricate vertically aligned TiO₂ nanowire–TiO₂ nanosheet–ZnO nanorod (TNW–TNS–ZNR) hyperbranched heterostructured arrays on TCO substrates as excellent anode material electrodes for efficient solar-to-electricity conversion. As a result, the TNW–TNS–ZNR heterostructured array based quantum dot-sensitized solar cells (QDSSCs) have exhibited an improved power conversion efficiency (PCE) under AM 1.5G one sun illumination, along with considerable improvement of short-circuit current density (J_sc), open voltage (V_oc) and fill factor (FF) due to their superior light harvesting and excellent charge collection capability. Combined with the chemical bath deposited Cu₂S counter electrode, the eventual PCE of CdS/CdSe co-sensitized solar cells can be further boosted to as high as 5.38%.