Förster Resonance Energy Transfer in Aggregates of CdSe Colloidal Quantum Dots with Adsorbed meso-Tetra(3-pyridyl)porphyrin

The influence of meso-tetra(3-pyridyl)porphyrin (TPyP) on Forster resonance energy transfer (FRET) in aggregates of CdSe colloidal quantum dots (CQDs) has been studied. Upon the formation of such aggregates, interparticle FRET arises, leading to two effects. First, due to blinking, the observed luminescence quantum yield decreases. Second, due to inhomogeneous broadening of the optical spectra of CQDs, the luminescence band shifts to the long-wavelength side. The introduction of TPyP into the system leads to its adsorption on CQDs with multi-timescale kinetics. As a result, FRET from CQDs to TPyP arises, which effectively competes with FRET between CQDs themselves. As a result, the red shift arising due to aggregation of CQDs is significantly reduced. In this case, the dye adsorption has no effect on the position of the luminescence peak of the non-aggregated particles.