posted on 2015-12-17, 08:09authored byXin Li, Lydia W. Slyker, Valerie
M. Nichols, George Shu Heng Pau, Christopher J. Bardeen, Ming L. Tang
Hybrid
optoelectronic devices are attractive because they offer
the promise of low-cost, roll-to-roll fabrication. Despite this, energy
transfer between organic and inorganic interfaces is not well understood.
Device engineering on this class of solution-processed materials generally
focuses on replacing the long insulating ligands with short ones.
Here, we show that energy and charge transfer between an inorganic
nanocrystal (NC) donor and organic molecular acceptor is acutely sensitive
to the chemical moiety linking the two species. Our results reveal
that the CdS NCs have distinct binding sites for different chemical
species because only resonance energy transfer (RET) is observed for
the carboxylic-acid-functionalized ligand, while both RET and charge
transfer are observed for the amine-functionalized ligand. We observe
that the equilibrium constant for this static quenching term increases
with decreasing particle size. This finding offers a new approach
in the design of hybrid thin films for devices and NC probes based
on RET used for imaging, sensing, signal transduction, and photon
management.