Tailored near-infrared-emitting colloidal heterostructured quantum dots with enhanced visible light absorption for high performance photoelectrochemical cells

Abstract

Colloidal heterostructured CuGaS₂ (CGS)/CdS core/shell quantum dots (QDs) with a wurtzite (WZ) phase were synthesized via a facile two-step technique. As compared to the bare CGS QDs, the optical properties of such heterostructured CGS/CdS core/shell QDs were tailored to show largely enhanced light absorption in the visible range and an emission peak in the near-infrared (NIR) region at a wavelength of ∼816 nm. As proof of concept, these core/shell QDs were used as light absorbers to fabricate a photoelectrochemical (PEC) cell, which exhibited a maximum saturated photocurrent density of ∼6.5 mA cm⁻² and outstanding stability under standard one sun illumination (AM 1.5G, 100 mW cm⁻²). The results indicate that these NIR core/shell QDs are promising candidates for future QD-based optoelectronic technologies such as QD-sensitized solar cells (QDSCs).