The absorption spectra of 50 mg/mL PbS QDs film and a solution of PbS QDs in hexanes were collected as described in the methods section. The solid-state absorbance at 808 nm was calculated using the equation shown below to be 0.021. This was converted to be (3.0±0.4)%. We note that this is on a similar order of magnitude as the percent absorption measured using method 1.