Controlling dissolution of PbTe nanoparticles in organic solvents during liquid cell transmission electron microscopy

Abstract

We present direct visualization of the dynamics of oleic-acid-capped PbTe nanoparticles suspended in different organic solvents using liquid cell transmission electron microscopy. Liquid cell transmission electron microscopy is a powerful tool to directly observe the behavior of a variety of nanoparticles in liquids, but requires careful consideration and quantification of how the electron beam affects the systems being investigated. We find that etching and dissolution of PbTe nanoparticles occurs with a strong dependence on electron dose rate ranging from no perceivable effect on the nanoparticles with lower dose rates (50 e⁻ Å⁻² s⁻¹) to complete dissolution within seconds or minutes at higher dose rates (100 and 200 e⁻ Å⁻² s⁻¹). We propose that oxidative etching, resulting from the radiolysis of small amounts of water, causes the PbTe nanoparticles to dissolve after exposure to a threshold electron dose rate of 50 e⁻ Å⁻² s⁻¹.