Ultrafast Dynamics of Photogenerated Electrons in CdS Nanocluster Multilayers Assembled on Solid Substrates: Effects of Assembly and Electrode Potential

Abstract

The ultrafast dynamics of photogenerated electrons in multilayer assemblies of CdS nanoparticles prepared on quartz and indium-tin oxide (ITO) substrates were followed by femtosecond (fs) visible-pump/mid-IR probe spectroscopy. Based on the observation of the photoinduced transient absorption spectra in the broad mid-IR range at the multilayer assembly of CdS nanoparticles, the occupation and fast relaxation of higher electronic states (1P(e)) were clarified. As compared with the electron dynamics of isolated (dispersed in solution) nanoparticles, the decay of photoexcited electrons in the multilayer assembly was clearly accelerated probably due to both electron hopping and scattering during interparticle electron tunneling. By using an ITO electrode as a substrate, the effect of the electric field on the photoelectron dynamics in the multilayer assembly was also investigated in situ. Both the amplitude and lifetime of photoexcited electrons gradually reduced as the potential became more positive. This result was explained by considering the reduction of the interparticle tunneling probability and the increase in the electron-transfer rate from the CdS nanoparticle assembly to the ITO electrode.

Spectroelectrochemical Investigation of the Charge Carrier Kinetics of Gold‐Decorated Cadmium Chalcogenide Nanorods

“…It is reasonable and shown by literature that the way of linking particles onto ITO/MPTMS substrates is changing the impedance of the system ,. The organic ligand molecules at the surface of the particle and the distance between the nanoparticle and the ITO, which is defined by the linker molecules, can be interpreted as the tunneling barrier ,,…”

Metal Nanoparticles with Liquid‐Crystalline Ligands: Controlling Nanoparticle Superlattice Structure and Properties

“…In-depth understanding and mastering of this process is crucial for building efficient devices for energy storage and conversion, self-healing materials, smart drug delivery systems and so forth. [5][6][7] With appropriate tools in hand NOAs having predefined properties and a wealth of applications can be obtained, but two conditions must be met. [3,4] Such nanoparticle ordered aggregates (NOAs) are complex materials exhibiting collective properties very different from properties of single building blocks.…”

“…[3,4] Such nanoparticle ordered aggregates (NOAs) are complex materials exhibiting collective properties very different from properties of single building blocks. [5][6][7] With appropriate tools in hand NOAs having predefined properties and a wealth of applications can be obtained, but two conditions must be met. First, required functionalities should be introduced with the choice of nanoparticle core and surface coating and, second, precise control over NPs arrangement in space should be possible.…”