4 research outputs found
Evidence for Enhanced Electron Transfer by Multiple Contacts between Self-Assembled Organic Monolayers and Semiconductor Nanoparticles
This study presents results on the
charge transfer between CdSe
nanoparticles (NPs) and a gold substrate, when the NPs are attached
to the gold via self-assembled monolayers of alkanedithiols (DT) of
various lengths. The study examines the dependence of the photoinduced
charge transfer on the DT length. Two methods were applied for measuring
the charge transfer yield, surface photovoltage (SPV) and temperature
dependent photoluminescence. The results demonstrate a net transfer
of electrons from the NPs to the gold, under constant illumination.
Interestingly, the data reveal that the monolayer composed of 10 carbon
methylene chains displays an unusually efficient electron transfer,
which is attributed to a high local ligand density resulting in multiple
links between the NPs and the substrate
Spin-Controlled Photoluminescence in Hybrid Nanoparticles Purple Membrane System
Spin-dependent
photoluminescence (PL) quenching of CdSe nanoparticles
(NPs) has been explored in the hybrid system of CdSe NP purple membrane,
wild-type bacteriorhodopsin (bR) thin film on a ferromagnetic (Ni-alloy)
substrate. A significant change in the PL intensity from the CdSe
NPs has been observed when spin-specific charge transfer occurs between
the retinal and the magnetic substrate. This feature completely disappears
in a bR apo membrane (wild-type bacteriorhodopsin in which the retinal
protein covalent bond was cleaved), a bacteriorhodopsin mutant (D96N),
and a bacteriorhodopsin bearing a locked retinal chromophore (isomerization
of the crucial C13î—»C14 retinal double bond was prevented by
inserting a ring spanning this bond). The extent of spin-dependent
PL quenching of the CdSe NPs depends on the absorption of the retinal,
embedded in wild-type bacteriorhodopsin. Our result suggests that
spin-dependent charge transfer between the retinal and the substrate
controls the PL intensity from the NPs