Band Gap Modulation of Lead Sulfide QDs

Abstract

Lead sulfide quantum dots (QDs) were prepared by liquid phase method. The particle size can be controlled by changing the concentration of reactants and surfactant and the size of the QDs varies from 7[Formula: see text]nm to 20[Formula: see text]nm, which results in the change of the optical properties and the band gap of the particles. The optical band gap of lead sulfide QDs increased drastically with the decrease of the diameter of the sample QDs.

Effect of Thermal Annealing on Structure and Optical Properties of Poly(p-xylylene)–PbS Thin Films

“…While the Tauc-plot method played a crucial role in optical studies of amorphous systems, it has two severe drawbacks when applied to ensembles of nanoparticles in simple straightforward manner. First, the Tauc-plot method substantially changes the shape of absorption curve when applied to a spectrum within the wide energy range; thus, the choice of linear region for extrapolation becomes ambiguous . Second, for the ensemble of nanoparticles, the Tauc-plot method frequently gives E n values for n = 2 smaller than those for n = 1/2.…”