Electrostatic Formation of Quantum Dot/J-aggregate FRET Pairs in Solution

Publication Type:

Journal Article


J. Phys. Chem. C, ACS Publications, Volume 113, Issue 23, p.9986-9992 (2009)


2009, 2013 and earlier


We report the formation and photonic properties of CdSe/ZnS quantum dot (QD)/J-aggregate donor−acceptor Forster resonant energy transfer (FRET)
pairs that are electrostatically bound and dispersed in water. Assembly
occurs when the positively charged dye,
(TTBC), binds electrostatically to QDs that are coated with a negatively
charged amphiphilic polymer. QD/J-aggregate FRET pairs display the
broadband absorption in the visible and the ultraviolet (UV) part of the
spectrum typical of quantum dots, along with the narrow emission
linewidths characteristic of J-band emitters (∼12 nm full width at
half-maximum). We use dynamic light scattering, transmission electron
microscopy, photoluminescence spectroscopy, and photoluminescence
lifetimes to conclude that the size of the aggregates formed in the
presence of QDs is between 1−6 nm. We find the FRET radius of the
QD/J-aggregate to be 5.1 nm. We further demonstrate electrostatic binding
as a general synthetic strategy for these types of FRET pairs by attaching
a negatively charged J-aggregate (BIC) to a quantum dot coated with
positively charged ligands.