Identifying the mechanistic insights into PbSeO3 decomposition, during milling, to give way to PbSe: An experimental and theoretical approach

Abstract

This study has been designed with the aim to understand the stability of the as-milled PbSeO3 reaction product, which is considered the determining step associated with the mechanochemical synthesis of PbSe nanostructures. Herein, a detailed discussion of the transition pathway from PbSeO3 to PbSe nanostructures is proposed. Hence, the decomposition process of PbSeO3, during milling, is studied by X-ray diffraction. According to the Rietveld refinement, the largest PbSeO3 concentration is obtained after 2 h of milling; after that, it decreases as the milling time is increased. In addition, the chemical composition changes are studied via density functional theory (DFT) calculations because the changes have an impact on the electronic properties, especially the bandgap value (Eg) associated with the presence of oxygen. Furthermore, the DFT calculations are also used to understand the transition state (TS) -via the diffusion of O-atoms by the atomic layers- from PbSeO3 to PbSe. After the oxygen removal, an energetically expensive process of spatial rearrangement (∼26.97 kJ·mol−1) took place to obtain the ground state structure of PbSe. Therefore, this work provides a comprehensive understanding of the decomposition mechanism of PbSeO3 that allows to tune the electronic properties of devices based on PbSe nanostructures, which are concerned with surface chemical composition changes.