Predicting signatures of anisotropic resonance energy transfer in dye-functionalized nanoparticles

Abstract

Strategy to expose anisotropic signatures of resonance energy transfer (RET) in the photoluminescence (PL) from a single dye-functionalized nanoparticle (NP) irradiated with light linearly polarized along the bright plane or the dark axis of the NP.

Enhanced light-harvesting of protein-pigment complexes assisted by a quantum dot antenna

“…This transition dipole moment enters in the calculation of the inter-pigment and the QD → pigment (or viceversa) electronic coupling, in turn an essential ingredient in FRET rate (see Ref. [10,11] for details). [18,20] and the QD-WS-yy [13], together with the solar emission spectrum [21].…”

“…This symmetry generates a threefold degeneracy in the interband transition dipole moment of the QD, reflecting on favoured QD → dye FRET when the dye transition dipole moment orientation and position are aligned with specific QD crystal axes [25]. Anyhow, being more symmetric, zincblende should exhibit less anisotropy in the QD → dye FRET than wurtzite (hexagonal crystal system) [10,11]. We estimate the effective masses of quasiparticle electrons and heavy holes and dielectric constant of the alloy core, together with the valence and conduction band offset between core and shell materials, from a stoichiometry-based linear interpolation of analogous data for CdSe and CdTe bulk materials [24,26].…”

“…Our theoretical description relies on a kinetic model for the evolution of the excited state population in the pigments and the QD, considering competitive absorption, FRET and decay channels (as in Ref. [11]). All QDpigment, pigment -QD, as well as inter-pigment energy transfer are included.…”

“…A detailed account on kinetic model and the calculation of rates for each of these processes have been presented elsewhere (see Ref. [10,11]). We calculate the photoexcitation spectrum of the dyes from the total fluorescence rate at the steady state as a function of the absorption wavelength.…”

“…Therefore, by placing adequately the protein-pigment complex with respect to the QD one might tune its overall QD-protein energy-transfer efficiency to its highest value. We have recently shown [10,11] that prediction of optimal quantum efficiency can be readily obtained by a theoretical model which takes into account the position and orientation of the fragments in the nanoassembly, the atomistic structure of the dyes and the crystal symmetries QDs in the transfer rates entering a kinetic equation approach. Our approach also provides a clear physical picture of the results.…”