InP/ZnS quantum dots stabilized with oleylamine ligands, fluorescence λem 650 nm, 5 mg/mL in toluene

InP/ZnS quantum dots

Introduction

InP/ZnS quantum dots are a type of core-shell nanomaterial composed of Indium Phosphide (InP) as the core and Zinc Sulfide (ZnS) as the shell. These quantum dots have gained significant attention in various scientific fields due to their unique size-dependent electronic and optical properties, which arise from the quantum confinement effect.

Indium Phosphide (InP) is a III-V compound semiconductor that offers excellent optical properties, including high photoluminescence quantum yield and relatively narrow emission spectra. InP-based quantum dots are often favored over their traditional Cd-based quantum dots (like CdSe) due to their less toxic nature, making them more attractive for a wide range of applications, especially in biomedicine and environmental sciences.

Zinc Sulfide (ZnS), a II-VI semiconductor, is used as a shell material to encapsulate the InP core. The ZnS shell serves to passivate the surface of the quantum dot, reducing surface defects and enhancing the photoluminescence properties by preventing non-radiative recombination. The shell also provides protection to the core material, improving the stability of the quantum dot, especially under harsh environmental conditions like oxidation and moisture.

Properties

Size-Tunable Optical Properties:

The bandgap of InP/ZnS quantum dots can be tuned by varying the size of the quantum dots, which shifts both the absorption and emission wavelengths. This feature makes them highly versatile for applications that require specific wavelengths of light.

The emission range typically spans from the visible spectrum to the near-infrared (NIR), depending on the size of the quantum dots.

High Photoluminescence Efficiency:

InP core quantum dots generally exhibit lower quantum yields compared to CdSe, but the incorporation of a ZnS shell greatly enhances the quantum yield, leading to higher photoluminescence efficiency.