CuInS2/CdS-Heterostructured Nanotetrapods by Seeded Growth and Their Photovoltaic Properties

We investigate a seeded-growth method for the synthesis of CuInS2 (core)/CdS (arm)-heterostructured nanotetrapods (HNTs), in which wurtzite CdS arms grow on CuInS2-core quantum dot seeds with tunable lengths. The CdS arms of the nanocrystal tetrapods effectively passivate the unstable surface defects and improve the photoluminescence quantum efficiencies to above 40%. Owing to spatially separated quasi-type-II excitons, efficient electron transport along the elongated arms, and enhanced light-absorption capabilities, the CuInS2/CdS-HNT-sensitized solar-cell device exhibits a more than 3-fold increase in the power conversion efficiency compared to that of the control CuInS2@CdS (core@shell) quantum dot device. We believe that the high photoenergy conversion abilities of the quasi-type-II CuInS2/CdS HNTs make them potential candidate materials for use in cost-effective and highly efficient solar cells.