In search of heavy metal-free mid-IR active colloidal materials, self-doped silver selenide colloidal quantum dots (CQDs) can be an alternative offering tunable mid-IR wavelength with a narrow bandwidth. One of the challenges in the study of the intraband transition is developing a method to widen the intraband transition energy range as well as reducing the toxicity of the materials. Here, we present AgxSe (x > 2) CQDs exhibiting an intraband transition up to 0.39 eV, produced by the cation exchange (CE) method from PbSe CQDs. The major electronic transition efficiently changes from the SWIR band gap of PbSe CQDs to the mid-IR intraband transition of the AgxSe CQDs by the CE. The intraband exciton is verified by examining the absorption and emission of the CE AgxSe CQDs as well as their applications on electrochemical mid-IR luminescence and mid-IR intraband photodetectors.
Bibliographical noteFunding Information:
K.S.J. thanks Hionsuck Baik (Korea Basic Science Institute, Seoul Center, Korea) for helping us in measuring the HAADF-STEM of the CQDs. This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MIST) (NRF-2021R1A2C2092053 and NRF-2019M3D1A1078299).
© 2022 American Chemical Society.
ASJC Scopus subject areas
- Materials Science(all)
- Physical and Theoretical Chemistry