Room Temperature Synthesis of Self-Doped Silver Selenide Quantum Dots Sensitive to Mid-infrared Light

Self-doped silver selenide colloidal quantum dots (CQDs) that harness intraband transition as a major electronic transition in steady-state have emerged as an alternative mid-infrared (IR)-sensitive material to Pb or Hg-based CQDs. Comparable to the previously reported hot-injection and cation-exchange methods for the self-doped Ag2Se CQDs synthesis, a facile synthesis method of the self-doped AgxSe (x ≥ 2) CQDs is reported that does not require high reaction temperature, reduces the cost of material synthesis, and enables widespread use of the self-doped nontoxic CQDs in various environments and applications. Through careful investigation of the crystal structure, compositional analysis, mid-IR absorption, photoluminescence, and photocurrent response, we demonstrate that the as-synthesized AgxSe CQDs exhibit peculiar optical and electrical properties of the self-doped CQDs, potentially highlighting their application as IR-active materials for mid-IR-based optoelectronics.