AgInS₂ (AIS) QDs are promising representatives of ternary nanocrystals with relatively wide bandgap between 1.87 and 2.03 eV depending on the underlying crystal structure (orthorhombic or tetragonal) [1]. However, even synthesized in the most appropriate conditions the aqueous AIS nanocrystals often possess a low (less than 10 %) quantum yield due to numerous surface defects and high surface to volume ratio. The common approach to increase the photoluminescence (Pl) intensity is to cover the crude AIS seeds with a shall of a material with a wider band gap, most often ZnS. Here we report an improved synthesis of AIS and AZIS nanocrystals with an extended emission range reaching the green spectral region while keeping the excellent stability of the colloidal solutions. Modification of AIS nanocrystals with Zn ions leads to hypochromic shift of the Pl maximum, increase of the Pl intensity, and broadening of the Pl spectra. Such changes to different extents were observed for each sample AIS3, AIS7, AIS11, AIS15, AIS17 and AIS20. The greenest AZIS nanoparticles with Pl maximum located at 505 nm were obtained at [In]/[Ag] feeding ratio 20. The highest quantum yield (25%) is inherent to the AZIS7 sample.  
The blue shift of Pl maximum of AIS nanocrystals modified with Zn²⁺ indicates an alloying, cation interdiffusion or etching of AIS core in addition to the ZnS shell formation [2]. The above-mentioned dynamic processes are competitive in the reactive solution and the outcome depends on a lot of specific conditions, such as concentration of precursors, nature of ligands, temperature or precursor feeding rate.
 The changes in the cation composition of AIS nanocrystal reveal that in our case partial etching of In-Ag pairs occurs as a result of Zn modification. AZIS QDs obtained by Zn treatment of AIS cores with In intraparticle deficiency or a small excess of In (AZIS3-AZIS7) possess a lower [In]/[Ag] intraparticle ratio than the initial AIS cores. Zn treatment of AIS11 and AIS17 samples does not change the [In]/[Ag] ratio, while AZIS20 QDs conversely possess a higher [In]/[Ag] intraparticle ratio than the initial cores. This ratio inversion can be explained by the replacement of one In-Ag pair with two Zinc atoms according to the scheme: 
2Zn²⁺ ↔ Ag⁺ + In³⁺
as equimolar substitution of both ions increases the fraction of more abundant components.
The replacement of the In-Ag cation pair by Zn atoms is also confirmed by the elimination of several inter- and intraband absorption transitions of Zn treated AIS cores as shown at the PLE spectra of AIS and AZIS colloids. Initial AIS nanocrystals demonstrate up to 4 absorption transitions. Peak A is observed for AIS3 and less pronounced for AIS7 sample so it can be attributed to the transition between the valence band and donor level, created by Ag_i as was discussed above. It finally disappears in the course of Zn treatment. Peak B matches perfectly with the E_g of the AIS nanocrystals, therefore we relate it with the excitonic transitions. Peaks C and D correspond to high energy intraband transitions to levels probably created by In atoms. Zn alloying also raises the position of the conduction band in all samples. Complete elimination of peak A and a slight decrease of peaks B and C in the case of AZIS3 sample confirmed that the majority of Ag_i  was etched while almost all In atoms.