Ultrafast carrier dynamics in Ag-CdTe hybrid nanostructure: non-radiative and radiative relaxations.

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 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 get 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.