A facile synthesis of alloyed Mn-doped ZnSeS nanoparticles using a modified selenium/sulfur precursor in a one-pot approach

Highly luminescent Mn doped ZnSeS nanoparticles have been synthesized using a modified Se/S-precursor solution in a facile one-pot approach. The main challenge of the phosphine-free synthesis of metal selenide nanoparticles is the solubility and reduction of elemental selenium in organic solvents without the use of alkylphosphine. Herein, we report on a highly reactive Se/S precursor solution with NaBH₄, which is suitable for the reproducible synthesis of alloyed structures like ZnSeS in a one-pot approach. Hitherto, the synthesis of core/shell and alloyed ZnSe nanoparticles like ZnSe:Mn/ZnS has required at least two steps with time consuming purification steps. This modified Se/S-precursor facilitates the synthesis of highly luminescent alloyed nanostructures in view of time and purification steps. The as-synthesized alloyed ZnSeS:Mn nanoparticles possess small size and high quality optical properties with up to 42% photoluminescence (PL) quantum yield (QY). Distinctive features in the PL spectra indicate the usability of the modified Se/S-precursor solution for the synthesis of alloyed structures. Besides this, the ratio of S to Se significantly affected the PL QY of the nanoparticles. ICP-MS/ICP-OES, EDX and XPS measurements indicate the formation of alloyed ZnSeS:Mn nanoparticles, using the modified precursor.