Ternary Ag<sub>3</sub>AuS<sub>2</sub> Nanocrystals\nfor Thin-Film Solar Cells

The concept of clean and pollution-free energy development\nhas\npromoted the rise of environmentally friendly silver-based chalcogenide\nnanocrystal (NC) solar cells, but currently reported silver-based\nNCs need complex synthesis processes at high temperatures that may\nbring zerovalent noble metal impurities for their high redox potentials.\nIn this study, we report a facile synthesis of novel Ag<sub>3</sub>AuS<sub>2</sub> NCs by injecting highly active oleylamine sulfur\ncomplexes as sulfur sources into metal precursor solutions at low\ntemperatures of 60 °C. The obtained Ag<sub>3</sub>AuS<sub>2</sub> NCs exhibit broad absorption spectra and high molar extinction coefficients\n(10<sup>6</sup> M<sup>–1</sup> cm<sup>–1</sup>). Then,\nthe Ag<sub>3</sub>AuS<sub>2</sub> NCs are applied as the light-absorbing\nactive layer in environmentally friendly thin-film solar cells. By\nintroducing a hybrid mixture of charge acceptors and donors (NCs/P3HT\nhybrid film) at the interface, the device gains an absorption increment\nand enhanced charge extraction, achieving a final power conversion\nefficiency of 3.38%. This work demonstrates the enormous potential\nof Ag<sub>3</sub>AuS<sub>2</sub> NCs from low-temperature preparation\nfor photovoltaic applications.