2 research outputs found
Study of the quantum efficiency of the excitonic optical amplification of nanosensors by linear and rainbow nonlinear optical spectroscopy
Quantum efficiency of excitonic enhancement in nanosensors by rainbow nonlinear optical spectroscopy
editorial reviewedQuantum dots (QD) constitute a novel generation of fluorescent probes due to their confined size in the 1-10 nm range. In this field, nanosensors sensitivity is of pivotal importance to target biomolecules. We focus here on the grafting of organic ligand-coated CdTe QDs monolayers on glass surfaces to address the environmental problem and cost of nanosensors. QD monolayers samples are pre-characterized by UV-VIS absorption and (Time-resolved) fluorescence emission, evidencing the success of transferring the QD optoelectronic properties from colloidal solution to amine-terminated aliphatic organosilane monolayer-modified glass samples. Moreover, from time-resolved fluorescence spectroscopy, the effect of chemical structure of monolayers are seen from a fast-quenching phenomenon in relation to colloidal QD solution. Afterwards, an advanced surface-specific spectroscopic tool, non-linear optical Two-Colour IR-Visible Sum-Frequency Generation spectroscopy (2C-SFG), is used to probe and evidences the dipolar coupling between QD excitons and their molecular surroundings, which improves the nanosensor’s detection threshold. This electro-optical coupling (inorganic-organic charge transfer) is modelled in an original formalism we developed and based on Feynman loop-diagrams