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

Abstract

Understanding the growth mechanism of AgInS 2 nanoparticles could benefit the designed growth of I−III−VI 2 nanomaterials and their applications in photonics, optoelectronics, etc. Herein, using tris(dibutyldithiocarbamate) indium(III) [In((C 4 H 9 ) 2 NCS 2 ) 3 ] ([InR 3 ]) and dibutyldithiocarbamate silver(I) [Ag((C 4 H 9 ) 2 NCS 2 )] ([AgR]) precursors, AgInS 2 -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, [InR 3 ]/DDT, [AgR]/OLA, and [InR 3 ]/OLA were used herein to describe the decomposition steps. In DDT, the decomposition activity of [AgR]/ DDT was much higher than that of [InR 3 ]/DDT; thus, the sequential decomposition of [AgR]/DDT and [InR 3 ]/DDT led to the formation of the Ag 2 S nanoparticles intermediate first, which then reacted with [InR 3 ]/DDT to form metastable o-AgInS 2 nanoparticles via the cation exchange and alloy process, and finally evolved into o-AgInS 2 @InS x core@shell nanoparticles, while in OLA, the decomposition activity of [AgR]/OLA was slightly higher than that of [InR 3 ]/OLA. Thus, the quasi-co-decomposition of [AgR]/OLA and [InR 3 ]/OLA led to the formation of Ag-rich Ag−In−S amorphous nanoparticles intermediate first and then quickly evolved into stable t-AgInS 2 /InS x nanoparticles. In addition, the photoluminescence quantum yield (PLQY) of t-AgInS 2 /InS x nanoparticles was higher than that of o-AgInS 2 @InS x nanoparticles.