Förster Resonance Energy Transfer Distance Dependence from Upconverting Nanoparticles to Quantum Dots

Abstract

Förster resonant energy transfer (FRET) with upconverting nanoparticles (UC-NPs) as donors and quantum dots (QDs) as acceptors has been regarded as a promising tool for biosensing applications. In this work, we use time-resolved fluorescence spectroscopy to analyze the UCNP-to-QD FRET and we focus on the most relevant parameter of the FRET phenomenon, UCNP-QD distance. This distance is controlled by a nanometric silica shell around the UCNP surface. We theoretically reproduce the experimental results applying FRET theory to the distribution of emitting erbium ions in the UCNP. This simple model allows us to estimate the contribution of every erbium 1 ion to the final FRET response and to explore different strategies to improve FRET efficiency. Abbreviations FRET, QD, UCNP KeywordsFörster resonance energy transfer, upconversion, quantum dot

SiO2‐Coated ZnO Nanoflakes Decorated with Ag Nanoparticles for Photocatalytic Water Oxidation

“…The insulating layer of less than 10 nm ( Figure 7C)i sp robably thin enough to allow energy transfer from ZnO to Ag NPs ruled by FRET.I nf act, the efficiencyo fF RET increases as the distance between the energy-donor and -acceptor species decreases. [25,26] In this configuration, FRET from ZnO to Ag NPs appearst ob et he dominant mechanism;n onetheless, energetic communication (PIRET) from Ag NPs towards ZnO could be hypothesised as stillt aking place. CAT6 is characterisedb ya SiO 2 layer of about 40 nm and, even if plasmon excitation could occur,t he shell is presumably too thick to allow energetic communication between ZnO and Ag NPs and vice versa, resulting in aZ nO quantum yield comparable to that of CAT1 ( Figure 7D).…”

Ensemble Effects in the Temperature‐Dependent Photoluminescence of Silicon Nanocrystals

“…The Fçrster distance R 0 for semiconductor nanoparticles is estimated to be around 5nm, although no specific value for R 0 between SiNCs is available. [43,44] Based on the chain length of dodecane (ca. 1.5 nm), we estimate the maximum interparticle distance to be around3nm, assuming there is no ligand intercalation but densely packedl ayers.…”

Impact of FRET between Molecular Aggregates and Quantum Dots

“…Although QDs have a range of promising properties, improving their photocurrent‐conversion efficiency remains a challenging task, owing to limited absorption within the solar spectrum and energy loss owing to ultrafast exciton annihilation. Förster resonance energy transfer (FRET) has been employed through the coupling of QDs with different materials (e.g., semiconductors and dyes) to allow for their use in light‐harvesting applications …”

“…Fçrsterr esonancee nergy transfer (FRET)h as been employed through the coupling of QDsw ith different materials (e.g.,s emiconductors and dyes) to allow for their use in light-harvesting applications. [17][18][19][20] Energy transfer is an onradiative phenomenon in whicha n excited donor transfers its energy to an acceptor through long-range dipole-dipole interactions. [21,22] The spectroscopic overlap between the donor emissiona nd the acceptora bsorption is the key factor in determiningt he rate and efficiency of the energy-transfer process.…”

“…[21,22] The spectroscopic overlap between the donor emissiona nd the acceptora bsorption is the key factor in determiningt he rate and efficiency of the energy-transfer process. In addition, the FRET process is distance-dependent [17,23] and, in the case of semiconductor nanocrystals, varies with surface properties. [24] The FRET process is well-known in ar ange of systems, such as metal-nanoparticle/dye surfaces, [25] metal-semiconductor-heterostructure composites, [26] and semiconductor-semiconductor systems (solid state, which is distance-independent).…”