Ultrafast Carrier Dynamics in Ag-CdTe Hybrid Nanostructure: Non-radiative and Radiative Relaxations

TL;DR

This study investigates ultrafast non-radiative and radiative relaxation processes in Ag-CdTe hybrid nanostructures, revealing faster hot electron recovery, increased QD contribution, and quenched radiative relaxation due to metal-semiconductor interactions.

Contribution

It provides new insights into charge transport and photoluminescence quenching mechanisms in metal-semiconductor hybrid nanostructures using transient transmission spectroscopy.

Findings

Faster hot electron recovery at picosecond timescales.

Increased contribution of CdTe QDs in the presence of Ag nanoparticles.

Quenching of radiative relaxation in CdTe QDs when coupled with Ag NPs.

Abstract

In this article, we study non-radiative and radiative relaxation processes in a hybrid formed by combining Ag nanoparticle (NP) and CdTe quantum dots (QD) using transient transmission spectroscopy. The ultrafast transient transmission of hybrid, when excited at 400 nm, shows a faster recovery of hot electrons at a shorter time scale (few picoseconds) while it shows a slower recovery at a longer time scale (few tens of picoseconds). Further, it is found that the contribution of CdTe QD to the transient transmission is increased in the presence of Ag NP. However, the radiative relaxation in CdTe QDs gets quenched in the presence of Ag NP. This work provides significant insight into the various relaxation processes that leads to the charge transport and PL quenching mechanisms in metal-semiconductor hybrids.