Size‐Dependent Synthesis of Cu12Sb4S13 Nanocrystals with Bandgap Tunability

Copper antimony sulfide (CAS) is an attractive material with a suitable bandgap for sunlight absorption and a high absorption coefficient in solar cells. There are few works focused on the size‐controllable synthesis of CAS nanocrystals, and no work reports on the special character of bandgap tunability until now. Herein, high‐quality monodispersed tetrahedrite (Cu₁₂Sb₄S₁₃) nanocrystals are synthesized through a novel solution‐based method by using thiols as ligands. The as‐prepared Cu₁₂Sb₄S₁₃ nanocrystals have a narrow size distribution and wide size range from 2 to 16 nm, while their absorption band edges are continuously tunable from 620 to 780 nm. The quantum size effects with bandgap tunability of Cu₁₂Sb₄S₁₃ nanocrystals are observed for the first time.