Highly reactive, flexible yet green Se precursor for metal selenide nanocrystals: Se-octadecene suspension (Se-SUS)

A suspension of fine selenium (Se) powder (100 or 200 mesh) in octadecene (Se-SUS) has proven to be a high-performance, versatile, convenient, reproducible, yet green Se precursor. The advantages of Se-SUS arise from its highly reactive chemical nature and flexibility. These two features made it possible to carry out the synthesis of high quality metal selenide nanocrystals with diverse compositions and structures, including binary, core/shell, transition metal doped, and complex composition nanocrystals. These successes further demonstrated that Se-SUS is a powerful Se precursor for solving a few long-standing challenges in the synthesis of high quality selenide nanocrystals. For instance, Se-SUS was successfully employed as a Se precursor for shell growth in high quality core/shell nanocrystals to replace expensive and highly toxic precursors, such as Se-phosphine and bis-trimethylsilyl selenide, with greatly lowered epitaxial temperatures (as low as 150 ℃) to avoid alloying. As another example, Se-SUS enabled "co-nucleation doping" as a means of preparing high quality Mn doped ZnSe nanocrystals with pure, stable, and highly efficient dopant fluorescence.