Synthesis and Characterization of Ag8(Ge1-x,Snx)(S6-y,Sey) Colloidal Nanocrystals

A facile colloidal approach to synthesize Ag-8(Ge1-x,Sn-x)(S6-y,Se-y) nanocrystals (NCs) in a highly controlled way across the entire compositional ranges (0 <= x <= 1, 0 <= y <= 6) has been developed. The NCs exhibit a uniform size distribution, highly crystalline structure, over 1 g scalable synthesis, and tunable band gaps in the range of 0.88-1.45 eV by varying their chemical compositions. The Ag8GeS6 NCs with a band gap of approximately 1.45 eV were employed as a model light harvester to assess their applicability in solar cells by a full solution-processing device, yielding an efficiency of 0.28% under AM1.5 illumination, demonstrating their application potential in solar energy utilization.