Composition-tunable Cu2(Ge(1-x),Sn(x))(S(3-y),Se(y)) colloidal nanocrystals: synthesis and characterization.

A facile colloidal approach was developed to prepare cubic Cu2(Ge1-x,Snx)(S3-y,Sey) nanocrystals (NCs) (0 ≤ x ≤ 1, 0 ≤ y ≤ 3). The band gaps of the NCs can be tuned in the range of 1.35-2.45 eV by varying the chemical compositions, and the NCs display promising applications in solar energy utilization.