Ultrafast optical spectroscopy of semiconducting and plasmonic nanostructures and their hybrids

Abstract

The knowledge of the carrier dynamics in nanostructures is of fundamental importance for the development of (opto)electronic devices. This is true for semiconducting nanostructures as well as for plasmonic nanoparticles (NPs). Indeed, improvement of photocatalytic efficiencies by combining semiconductor and plasmonic nanostructures is one of the reasons why their ultrafast dynamics are intensively studied. In this work, we will review our activity on ultrafast spectroscopy in nanostructures carried out in the recently established EuroFEL Support Laboratory. We have investigated the dynamical plasmonic responses of metal NPs both in solution and in 2D and 3D arrays on surfaces, with particular attention being paid to the effects of the NP shape and to the conversion of absorbed light into heat on a nano-localized scale. We will summarize the results obtained on the carrier dynamics in nanostructured perovskites with emphasis on the hot-carrier dynamics and in semiconductor nanosystems such as ZnSe and Si nanowires, with particular attention to the band-gap bleaching dynamics. Subsequently, the study of semiconductor-metal NP hybrids, such as CeO2-Ag NPs, ZnSe-Ag NPs and ZnSe-Au NPs, allows the discussion of interaction mechanisms such as charge carrier transfer and Förster interaction. Finally, we assess an alternative method for the sensitization of wide band gap semiconductors to visible light by discussing the relationship between the carrier dynamics of TiO2 NPs and V-doped TiO2 NPs and their catalytic properties.

Effects of Crystal Morphology on the Hot-Carrier Dynamics in Mixed-Cation Hybrid Lead Halide Perovskites

“…Figure 1 reports the schematic representation of the FTAS setup used to perform the pump-probe measurements. Further details of the experimental set-up can be found in previous publications [35][36][37].…”

Silver Nanoparticles Functionalized by Fluorescein Isothiocyanate or Rhodamine B Isothiocyanate: Fluorescent and Plasmonic Materials

“…The instrument response function was measured to be approximately 50 fs. More experimental details of the setup can be found in previous publications [59].…”

Near‐Surface Buried Plasmonic Nanoparticles in Glass as Novel Nonlinear Saturable Absorbers for Ultrafast Lasers

“…[ 43 ] The “left‐negative” with “right‐positive” features round LSPR central wavelengths of the bleaching and induced absorption manifest redshifts of the LSPR following intra‐band pump excitation. [ 42,44 ] Figure 2c shows two typical TA spectra at 539 and 708 nm, respectively. The rise time of 217 fs is mainly determined by hot electrons thermalization.…”