Coloring Tetrahedral\nSemiconductors: Synthesis and\nPhotoluminescence Enhancement of Ternary II-III<sub>2</sub>‑VI<sub>4</sub> Colloidal Nanocrystals

Ternary tetrahedral\nII-III<sub>2</sub>-VI<sub>4</sub> semiconductors,\nwhere II is Zn or Cd, III In or Ga, and VI S, Se, or Te, are of interest\nin UV radiation detectors in medicine and space physics as well as\nCO<sub>2</sub> photoreduction under visible light. We synthesize colloidal\nII-III<sub>2</sub>-VI<sub>4</sub> semiconductor nanocrystals from\nreadily available precursors and ascertain their ternary nature by\nstructural and spectroscopic methods, including <sup>77</sup>Se solid-state\nNMR spectroscopy. The pyramidally shaped nanocrystals range between\n2 and 12 nm and exhibit optical gaps of 2–3.9 eV. In the presence\nof excess anions on the particle surface, treatment with Lewis acidic,\nZ-type ligands results in better passivation and enhanced photoluminescence.\nElectronic structure calculations reveal the most stable, lowest energy\npolymorphs and coloring patterns. This work will pave the way toward\nmore environmentally friendly, ternary semiconductors for optoelectronics\nand electrocatalysis.