Alkylthiol-Enabled Se Powder Dissolution in Oleylamine at Room Temperature for the Phosphine-Free Synthesis of Copper-Based Quaternary Selenide Nanocrystals

Enhancement of Se solubility in organic solvents without the use of alkylphosphine ligands is the key for phosphine-free synthesis of selenide semiconductor nanocrystals (NCs). In this communication, we demonstrate the dissolution of elemental Se in oleylamine by alkylthiol reduction at room temperature, which generates soluble alkylammonium selenide. This Se precursor is highly reactive for hot-injection synthesis of selenide semiconductor NCs, such as Cu2ZnSnSe4, Cu(InGa)Se-2, and CdSe. In the case of Cu2ZnSnSe4, for example, the as-synthesized NCs possessed small size, high size monodispersity, strong absorbance in the visible region, and in particular a promising increase in photocurrent under AM1.5 illumination. The current preparation of the Se, precursor is simple and convenient, which will promote the synthesis and practical applications of selenide NCs.

在不使用烷基膦配体的情况下提高硒在有机溶剂中的溶解度是无膦合成硒化物半导体纳米晶体的关键。在本文中，我们展示了在室温下通过烷基硫醇还原使元素硒在油胺中溶解，从而生成可溶的烷基铵硒化物。这种硒前体对于硒化物半导体纳米晶体（如Cu₂ZnSnSe₄、Cu(InGa)Se₂和CdSe）的热注入合成具有高反应活性。例如，对于Cu₂ZnSnSe₄而言，所合成的纳米晶体具有尺寸小、尺寸单分散性高、在可见光区域有强吸收的特点，特别是在AM1.5光照下光电流有显著提高。目前这种硒前体的制备简单方便，这将促进硒化物纳米晶体的合成和实际应用。