Near-infrared absorption–emission cross-sections of PbSe quantum dots doped in UV gel

Abstract

We measure near-infrared absorption spectra of PbSe quantum dots (QDs) with three sizes (4.5, 5.0, and 5.6nm) doped in UV gel with the concentration of 0.25–1.50mgmL−1 by using an absorption-spectrum method. An empirical formula is proposed to describe the correlation of the first–second absorption-peak wavelengths and QD size. The peak-absorption cross-section is measured as 2.76–3.69×10−16cm2 for 5.6-nm QD, and the absorption coefficient ranges in 0.19–0.59cm−1, both associated with the doping concentration and the QD size. Furthermore, the emission cross-sections are determined by measuring the photoluminescence spectra of QDs and using the McCumber relationship, which depend weakly on both the doping concentration and the QD size. For 5.6-nm QD, the measured peak-emission cross-section is 3.36–4.48×10−16cm2 within the range of experimental doping concentration.