Sulfur-source-dependent phase-selective preparation of Cu₃NiInSnS₆ nanocrystals and their optical and magnetic...

Multifunctional multinary metal chalcogenides have long been a research hotspot in the field of materials chemistry due to their rich composition, flexible structure, excellent properties and wide range of applications. However, the exploration of complex quinary chalcogenides is still challenging. In this work, for the first time, we have developed the controlled synthesis of quinary Cu₃NiInSnS₆ nanocrystals, realizing the selective preparation of hexagonal wurtzite and cubic zinc blende metastable phases by simply tuning the sulfur source. The phase structure analysis reveals that both metastable phases possess a disordered structure with a random distribution of metal atoms in the unit cells. The fabricated wurtzite and zinc blende-structure Cu₃NiInSnS₆ nanocrystals have a direct band gap of 1.82 and 1.94 eV, respectively, and both exhibit superparamagnetic behavior at low temperatures. This work is of great significance for the development of novel multifunctional materials based on metastable multinary metal chalcogenide phases.