Manipulating the Optoelectronic Properties of Quasi-type II CuInS<sub>2</sub>/CdS Core/Shell Quantum Dots for Photoelectrochemical Cell Applications
Changmeng Wang, Xin Tong, Wenhao Wang, Jingyin Xu, Lucas V. Besteiro, Ali Imran Channa, Feng Lin, Jiang Wu, Qiang Wang, Alexander O. Govorov, Alberto Vomiero, Zhiming M. Wang
Abstract
Colloidal core/shell heterostructured quantum dots (QDs) possessing quasi-type II band structure have demonstrated effective surface passivation and prolonged exciton lifetime, leading to enhanced charge separation/transfer efficiencies that are promising for photovoltaic device applications. Herein, we synthesized CuInS2 (CIS)/CdS core/shell heterostructured QDs and manipulated the optoelectronic properties via controlling the CdS shell thickness. The shell-thickness-dependent optical properties indicate the existence of a quasi-type II band structure in such core/shell QDs, which was verified by ultrafast spectroscopy and theoretical simulations. These quasi-type II core/shell QDs having various shell thicknesses are used as light absorbers for the fabrication of solar-driven QDs-based photoelectrochemical (PEC) devices, exhibiting an optimized photocurrent density of ∼6.0 mA/cm2 and excellent stability under simulated AM 1.5G solar illumination. The results demonstrate that quasi-type II CIS/CdS core/shell heterostructured QDs with tailored optoelectronic properties are promising to realize high-performance QDs-based solar energy conversion devices for the production of solar fuels.