Surface Modified

Colloidal semiconductor quantum dots (QDs) have attracted attention in various fields due to their unique size- and shape-dependent optical and electronic properties. In particular, their light-emitting characteristics in a wide range of wavelengths, i.e., from ultraviolet to near-infrared, makes them a new class of emitters for various technological applications such as biomedical imaging, light-emitting diodes, and  lasers.

As of today, various semiconductors (including the II−VI and III−V families) have been suggested for such uses, and InP QDs can be recognized as important candidates for Cd-free environmentally benign emitters, operating across the entire visible range.

InP QDs in nanoscale strongly absorb light when the excitation energy is greater than the bandgap energy. Electrons are promoted from the valance to the conduction band. The energy of the quantum confinement peak depends on the size, shape and structure core@shell.The PL emission efficiency of InP/ZNS NCs increases significantly with increasing the synthesis temperature.

The InP particle size increases with the increase in temperature. This remarkable enhancement in optical properties is due to the successful surface passivation of the InP cores with ZnS shells of wider band gap energy. The ZnS shells structurally passivate the dangling bonds on the surface of the cores and also energetically suppress the leakage of excitons from the cores into the shell because of its wider band gap energy as compared to that of the core.

When the surface of InP is passivated byZns,core shell quantum dots is formed and the quantum yield and Photo Lumniscence efficiency is greatly improved compared to that with bare InP.Beside the optical transitions in the InP core, the optical processes within the ZnS shell strongly influence the dynamics of carriers’ population and evolution after photo-generation.