The mechanochemical synthesis of PbTe nanostructures: following the Ostwald ripening effect during milling

Abstract

A fundamental understanding of the Ostwald ripening effect (ORE) during the mechanochemical synthesis of PbTe nanostructures is presented.

Oriented-Attachment- and Defect-Dependent PbTe Quantum Dots Growth: Shape Transformations Supported by Experimental Insights and DFT Calculations

“…As shown in Figure 1a,b, under the same milling conditions (3 h), the QDs start to assemble together and aggregate into rounded PbTe QDs to minimize their surface area. 19 This process takes place through the mechanism known as OA, as has been reported for other lead chalcogenides and other semiconductors. 31−33 After 5 h of milling, the growth of PbTe QDs with a relatively perfect lattice can be observed (see the TEM results in Figure 1c).…”

“…Due to the presence of oxygen in the milling atmosphere, an overstoichiometric Te addition was considered to obtain the just PbTe composition. 19 The HEM process was carried out using an 8000 Mixer/Mill with a ball-to-powder mass ratio fixed at 10:1. The HEM process was carried out for up to 5 h to trace the mechanisms of formation of the PbTe QDs under c−P−T vial conditions.…”

“…In this sense, it has been reported that structural defects in PbTe serve as sites to induce coalescence. 19,34 Hence, a decrement in the excess energy associated with the interfaces is expected because distorted QDs (∼5 nm) are dissolved to form bigger ones (∼6.5 nm).…”

“…The Pb–Te powder mixtures (with a nominal composition of Pb–Te) were sealed together with 50 g of ZrO 2 spheres (10 mm-Ø balls) into a cylindrical Nylamid vial (an inner volume of 60 cm 3 ). Due to the presence of oxygen in the milling atmosphere, an overstoichiometric Te addition was considered to obtain the just PbTe composition …”

“…17,18 Experimentally, two of the main barriers for the scalable synthesis of QDs via a low-cost method are the Ostwald ripening effect (ORE) and, in parallel, the lack of strategies that allow us to control the size, shape, and stability of the IV− VI semiconductor QDs in a large scale. 19 During the highenergy milling (HEM) process, the decrement in the excess energy associated with the interfaces under the milling conditions is avoided to obtain dispersed QDs; 19 consequently, it is an ongoing research challenge.…”