Photoinduced electron transfer from colloidal cadmium sulfide to methylviologen: a picosecond transient absorption study

Abstract

255complex so much increases the density of rovibronic levels that all resolution of AlO-based vibrational level structure is lost in excited-state complex formation.I0 ConclusionThe results obtained thus far indicate that using an extrapolation of the techniques we have outlined here, it will be possible to (1) evaluate nontransition-metal M(C0)2 (x = 1,2) binding energies, (2) study long-lived metal oxide-carbon dioxide solvation complexes formed in metal-C02 complex oxidation, and (3) characterize the spectroscopy of M-CO and M-C02 complexes. We believe that these metal atom based solvation complexes present an opportunity to study the middle ground region extending in various degrees from weak binding van der Waals interactions to strong chemical bonding.The spectra in Figure 3 suggest that C02 complex formation or solvation presents only a small perturbation to the electronic spectrum of the metal oxide. Not only do these results indicate that we are dealing with relatively weak binding of the C 0 2 to the product metal oxide producing a highly perturbed metal oxide excited electronic state, but also, in conjunction with recent results obtained when the transition metals are entrained in CO and subsequently oxidized with O3 or N02,6 these results indicate that the spectra of MCO , M(CO),, and M-C02 complexes might be observed through a variety of spectroscopies in the vicinity of known atomic transitions for the metal atoms of interest.Picosecond optical pumpprobe spectroscopy was used to measure electronic energy relaxation in aggregates of pseudoisocyanine on 40-A-diameter colloidal silica particles. The adsorption of pseudoisocyanine on colloidal silica wds accompanied by the appearance of a sharp band at 569 nm, called the J-band, in the absorption spectrum. The J-band arises from an optical transition to a single-exciton state of aggregates absorbed on colloids. Nonexponential signals obtained from transient optical bleaching of the J-band are discussed in terms of a polariton model.

Spectroscopic elucidation of energy transfer in hybrid inorganic–biological organisms for solar-to-chemical production

“…A multiexponential decay unsurprisingly indicates several processes at play in the complex M. thermoacetica-CdS hybrids. Rapid picosecond decays were previously measured with colloidal CdS that featured molecular acceptors with fast e − transfer behavior (24)(25)(26). As hot e − relaxation in Cd-chalcogenide quantum dots occurs in the subpicosecond regime, this process does not likely contribute to the TA kinetics in the measured time scale (27).…”

Influences of proton-dissociation equilibrium of capping agents on the photo-chemical events of the colloidal solutions containing the thiol-capped cadmium sulfide particles

“…The time-resolved transient absorption spectra of semiconductor particles have also been investigated by a fast kinetic spectroscopy to clarify their primary photo-chemical events [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

Electron Shuttling Across the Interface of CdSe Nanoparticles Monitored by Femtosecond Laser Spectroscopy

“…31 Investigations of CdS NPs with methyl viologen cations as adsorbates (CdS-MV 2+ ) showed that MV 2+ is able to accept the photoexcited electron from the CdS NPs. 7,[32][33][34][35] Recently, the fem-tosecond dynamics of the charge carriers were studied and it was revealed that electron transfer takes place in 200-300 fs. 36 In the present work, we report on the femtosecond charge carrier dynamics of CdSe NP-quinone composites.…”