Inhibition of plasmonically enhanced interdot energy transfer in quantum dot solids via photo-oxidation

Journal of Applied Physics

Hatef

Nejat

et al. 2014

Self Cite

We studied plasmonic features of bimetallic nanostructures consisting of gold nanoisland cores semi-coated with a chromium layer and explored how they influence emission of CdSe/ZnS quantum dots. We showed that, compared with chromium-covered glass substrates without the gold cores, the bimetallic nanostructures could significantly enhance the emission of the quantum dots. We studied the impact of the excitation intensity and thickness of the chromium layer on this process and utilized numerical means to identify the mechanisms behind it. Our results suggest that when the chromium layer is thin, the enhancement process is the result of the bimetallic plasmonic features of the nanostructures. As the chromium layer becomes thick, the impact of the gold cores is screened and the enhancement mostly happens mostly via the field enhancement of chromium nanoparticles in the absence of significant energy transfer from the quantum dots to these nanoparticles. V

Section: Discussionmentioning

confidence: 99%

“…38 It has also been shown that such a photo-oxidation process can suppress plasmonic enhancement of energy transfer between QDs. 39…”

Section: Discussionmentioning

confidence: 99%

Plasmonic emission enhancement of colloidal quantum dots in the presence of bimetallic nanoparticles

Journal of Applied Physics

Hatef

Nejat

et al. 2014

Self Cite

“…The following equation reported by Chen may then be used to determine the change in CdSe QDs' radii due to photooxidation 16,41…”

Section: Figmentioning

confidence: 99%

“…15 We have also shown that when metallic nanoparticles are coated with an ultrathin layer of Cr oxide, the plasmonic enhancement of the energy transfer between CdSe/ZnS QDs can be suppressed with irradiation. 16 These prior results suggest that when a substrate is coated with an ultrathin layer of a specific metal oxide, it can be used as a photo-active substrate to study some of the characteristic features of QDs using the unique photocatalytic effects of the oxide. Utilizing such photo-active substrates (PASs), our objective in this paper is to investigate the impact of the structures of colloidal QDs, including their cores, shells, and ligands, on their photophysical and photochemical properties and the way such QDs interact with the environment (including the PASs) and light.…”

Section: Introductionmentioning

confidence: 99%

Probing the structural dependency of photoinduced properties of colloidal quantum dots using metal-oxide photo-active substrates

Patty

Journal of Applied Physics

Campbell

et al. 2014

We used photoactive substrates consisting of about 1 nm coating of a metal oxide on glass substrates to investigate the impact of the structures of colloidal quantum dots on their photophysical and photochemical properties. We showed during irradiation these substrates can interact uniquely with such quantum dots, inducing distinct forms of photo-induced processes when they have different cores, shells, or ligands. In particular, our results showed that for certain types of core-shell quantum dot structures an ultrathin layer of a metal oxide can reduce suppression of quantum efficiency of the quantum dots happening when they undergo extensive photo-oxidation. This suggests the possibility of shrinking the sizes of quantum dots without significant enhancement of their non-radiative decay rates. We show that such quantum dots are not influenced significantly by Coulomb blockade or photoionization, while those without a shell can undergo a large amount of photo-induced fluorescence enhancement via such blockade when they are in touch with the metal oxide.

“…13 When MNPs are coated with a ultrathin layer of Cr oxide and irradiated, this accelerated photo-oxidation can even supress plasmonic enhancement of F€ orster resonance energy transfer (FRET) between QDs. 14 In this paper, we investigated the emission of QDs when they were deposited on plasmon-metal oxide substrates. These substrates consisted of arrays of gold (Au) nanorods (NRs) embedded in a dielectric material and coated on the top with a nanometer-thin layer of Al oxide (Fig.…”

mentioning

confidence: 99%

Improvement of plasmonic enhancement of quantum dot emission via an intermediate silicon-aluminum oxide interface

Wing

Applied Physics Letters

Campbell

2015

We studied the emission of quantum dots in the presence of plasmon-metal oxide substrates, which consist of arrays of metallic nanorods embedded in amorphous silicon coated with a nanometer-thin layer of aluminum oxide on the top. We showed that the combined effects of plasmons and the silicon-aluminum oxide interface can lead to significant enhancement of the quantum efficiency of quantum dots. Our results show that such an interface can significantly enhance plasmonic effects of the nanorods via quantum dot-induced exciton-plasmon coupling, leading to partial polarization of the quantum dots' emission.