Quantum-dot size and thin-film dielectric constant: precision measurement and disparity with simple models

Publication Type:

Journal Article

Source:

Nano Lett., ACS Publications, Volume 15, Issue 1, p.21-26 (2015)

ISBN:

1530-6984

Keywords:

2015, Capacitance, Dielectric constant, PbS, quantum dot, SAXS

Abstract:

We study the dielectric constant of lead sulfide quantum dot (QD) films as a function of the volume fraction of QDs by varying the QD size and
keeping the ligand constant. We create a reliable QD sizing curve using
small-angle X-ray scattering (SAXS), thin-film SAXS to extract a
pair-distribution function for QD spacing, and a stacked-capacitor
geometry to measure the capacitance of the thin film. Our data support a
reduced dielectric constant in nanoparticles.