On the "chemical Inertness" of Teflon in Chemical Synthesis

Impurities in Teflon, a material which has become synonymous with chemical inertness, were found to strongly influence the short wave infrared (SWIR) response of solution-deposited PbS:Th thin films. Notable concentrations of Ca-containing compounds were detected in Teflon holders, which are routinely used in many experimental setups, including for solution deposition of semiconductor thin films. It was found that Ca2+ cations leached out from the Teflon sample holders into the aqueous deposition solution and contaminated the PbS:Th thin films. By identifying and subsequently removing the impurity source, the SWIR responsivity of the films was significantly improved.