Hot‐Injection Synthesized Ag₂S Quantum Dots with Broad Light Absorption and High Stability for Solar Cell Applications

Abstract A hot‐injection synthesis method was used to synthesize low‐toxicity Ag₂S colloidal quantum dots (CQDs) with strong and broad light absorption as an ultra‐thin photo‐absorber in CQD heterojunction solar cells. By using iodide and sulfur linkers it was possible to accomplish efficient charge carrier extraction, resulting in a high photocurrent due to the broad absorption spectrum. Transient photovoltage decay measurements were used to obtain information about trap states in the CQDs and the effect on the lifetime of the photoinduced carriers. The devices show very promising stability under constant long‐term illumination and they are stable under ambient storage conditions with low losses to the performance over a period of over two months. These results show that Ag₂S CQDs have high potential within solar cell applications, and point the direction for further improvements.