“…For ternary or quaternary semiconductors, the stoichiometric ratio of their elements is usually adjustable, which also plays an important role in their properties and device performance. 33,34 A variety of studies have been performed to investigate this stoichiometric effect on NCSs, and various NCSs with different element stoichiometry have been prepared, such as NiCo 2 S 4 , 19,35 CoNi 2 S 4 , 36,37 Ni 1.4 Co 1.6 S 4 , 38 Ni 1.5 Co 1.5 S 4 , 39 (Co 0.5 Ni 0.5 ) 9 S 8 , 40 (Ni 0.33 Co 0.67 ) 9 S 8 , 41 Ni 1.77 Co 1.23 S 4 , 42 Ni 4.5 Co 4.5 S 8 , 43 Ni 0.67 Co 0.33 S, 44 etc. The comparison of the relative performance of NCSs with different element stoichiometry has also been discussed in depth (Fig.…”