Colloidal Synthesis and Stability of LaS and MnSe Nanoparticles

• Kristina González-Vargas, Chemical Engineering, University of Delaware

• Emil Hernández-Pagán, Chemistry and Biochemistry, University of Delaware

Colloidal synthesis of nanoparticles from metals such as lanthanum and manganese receive less attention than other metals despite their potential applications. These particles exhibit a variety of polymorphs and phases, each suited for different purposes. The properties of materials are significantly affected by their structure; materials with the same composition can exhibit different behaviors if they have different crystal structures. Achieving control of the crystal structure of nanoparticles is a crucial step towards developing helpful materials for the future. Manganese selenide, for example, is known to have two different polymorphs: wurtzite and rock salt, as well as a pyrite phase. Various applications for these polymorphs have been analyzed, showing that rock salt is more effective for use in batteries than the others. Lanthanum sulfide nanoparticles are thought to have multiple applications, especially in the biomedical field. Previous experiments on manganese sulfide and manganese selenide showed that by varying the halide salt precursor, a different polymorph would be obtained. Inspired by that, lanthanum sulfide synthesis with different halide salts as precursors could be explored to gain control over the crystal structure. In addition to this, while studied previously, synthesized manganese selenide nanoparticles lack stability, giving little time for further analysis. Ensuring the stability of nanoparticles is crucial, as it allows for the examination of their properties days later. Adding additional ligands and varying the solvents could be implemented to prolong the stability of the nanoparticles.