Tailoring intraband transition via composition in self-doped Ag₂S_xSe_y alloy nanocrystals

Various optoelectronic devices heavily depend on the interband transitions in their materials, thereby restricting material choice based on the band gap. Hence, an investigation of intraband transitions, which involve electronic states within each band, holds the potential to broaden the range of material choice significantly and contribute to the development of innovative optoelectronic devices. Notably, stable mid-infrared intraband transitions have been observed in several colloidal quantum dots (CQDs), mostly toxic to date. However, the active tuning of the intraband transitions of CQDs, especially via composition, remains largely unexplored. To address this knowledge gap, the active control of intraband transitions in non-toxic Ag₂S_xSe_y alloy CQDs is demonstrated for the first time herein. This demonstration is expected to make a substantial contribution to the design of new materials for intraband transitions, thereby broadening the selection of materials available for intraband optoelectronic devices.