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

We measure near-infrared absorption spectra of PbSe quantum dots (QDs) with three sizes (4.5, 5.0, and 5.6 nm) doped in UV gel with the concentration of 0.25-1.50 mg mL−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 2.76-3.69×10−16 cm2 for 5.6-nm QD, and the absorption coefficient ranges in 0.19-0.59 cm−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 3.36-4.48×10−16 cm2 within the range of experimental doping concentration.