Ligands Induced the Growth of Colloidal AgInS2 Nanoparticles with Tuned Structure and Photoluminescence Property

Understanding the growth mechanism of AgInS2 nanoparticles could benefit the designed growth of I–III–VI2 nanomaterials and their applications in photonics, optoelectronics, etc. Herein, using tris­(dibutyldithiocarbamate) indium­(III) [In­((C4H9)2NCS2)3] ([InR3]) and dibutyldithiocarbamate silver­(I) [Ag­((C4H9)2NCS2)] ([AgR]) precursors, AgInS2-based nanoparticles with different structures have been synthesized in a controlled manner through a one-pot approach via different growth mechanisms in 1-dodecanethiol (DDT) and oleylamine (OLA), respectively. The DDT and OLA could participate in the decomposition of precursors; thus, the [AgR]/DDT, [InR3]/DDT, [AgR]/OLA, and [InR3]/OLA were used herein to describe the decomposition steps. In DDT, the decomposition activity of [AgR]/DDT was much higher than that of [InR3]/DDT; thus, the sequential decomposition of [AgR]/DDT and [InR3]/DDT led to the formation of the Ag2S nanoparticles intermediate first, which then reacted with [InR3]/DDT to form metastable o-AgInS2 nanoparticles via the cation exchange and alloy process, and finally evolved into o-AgInS2@InS x core@shell nanoparticles, while in OLA, the decomposition activity of [AgR]/OLA was slightly higher than that of [InR3]/OLA. Thus, the quasi-co-decomposition of [AgR]/OLA and [InR3]/OLA led to the formation of Ag-rich Ag–In–S amorphous nanoparticles intermediate first and then quickly evolved into stable t-AgInS2/InS x nanoparticles. In addition, the photoluminescence quantum yield (PLQY) of t-AgInS2/InS x nanoparticles was higher than that of o-AgInS2@InS x nanoparticles.