Electron Transfer as a Probe of the Permeability of Organic Monolayers on the Surfaces of Colloidal PbS Quantum Dots

KATHRYN E. KNOWLES; MARIO TAGLIAZUCCHI; MICHAL MALICKI; NATHANIEL K. SWENSON; EMILY A. WEISS

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2013 vol. 117 p. 15849 - 15857

1932-7447

ABSTRACT:Transient absorption measurements on both the picosecond andmicrosecond time scales reveal that the efficiencies with which a series of alkyl-substituted p-benzoquinone (s-BQ) molecules participate in static and collisionalphotoinduced electron transfer (PET) with colloidal PbS quantum dots (QDs) indichloromethane solution depend on both the size and shape of the s-BQ molecule.The efficiencies of both static and collisional PET are limited by the presence of theoleate ligand shell on the surface of the QDs and decrease with an increase inmolecular volume,VQ, of the s-BQ, in general; however, the substitution patternson the BQ ring that facilitate static PET are not the same patterns that facilitatecollisional PET. A model for the dependence of the collisional quenching efficiencyonVQallows quantitative characterization of both the permeability and average thickness of the oleate ligand shell of the QDs ina dichloromethane solution