Thursday june the 12th at 11am in room 4007 of BEM :
Colloidal quantum dots, also known as artificial atoms, are excellent semiconductor platform materials for exploring electronic transitions due to their wavelength tunability and transition selectivity. While extensive investigations have elucidated the tunability of interband transitions via quantum confinement, the exploration of intraband transitions remains comparatively nascent. Intriguingly, intraband transitions enable access to the transition energy smaller than the bulk bandgap energy inaccessible via conventional interband transitions. In this talk, I will present a systematic investigation of steady-state intraband transitions in various self-doped CQD systems. Parameters involved in the self-doping, such as surface dipoles, compositional non-stoichiometry, and electronic states, will be discussed. In addition, efforts to substitute traditionally toxic elements with environmentally benign alternatives will also be discussed, with the aim of developing low-toxicity CQDs that retain optical properties. The self-doped quantum dot can provide an understanding of the unexplored quantum-plasmon resonances where both characters of semiconductor nanocrystals and metal nanocrystals are co-present. Additionally, nonlinear infrared lasing of narrow bandgap tellurium microcrystal semiconductors and their applications will also be discussed. This study highlights the fundamental understanding and materials design principles needed to harness this regime for future optoelectronic and infrared photonic applications.
Reference
[1] Ultranarrow Mid-infrared Quantum Plasmon Resonance of Self-Doped Silver Selenide Nanocrystal
ACS Nano, 2023, 17, 17, 16895-16903.
[2] Extended- Short-Wavelength Infrared Photoluminescence and Photocurrent of Nonstoichiometric Silver Telluride Colloidal Nanocrystals Nano Lett. 2021, 21(19) 8073-8079.
[3] Ultrafast Intraband Auger Process in Self-doped Colloidal Quantum Dots Matter, 2021, 4, 1072-1086.
[4] Transformation of Colloidal Quantum Dot : From Intraband to Localized Surface Plasmon Resonance Nano Lett., 2020, 20, 4985-4992.
[5] Mid-Infrared Intraband Transition of Metal Excess Colloidal Ag2Se Nanocrystals ACS Photonics, 2018, 5, 1907-1911.
[6] Midwavelength Infrared Photoluminescence and Lasing of Tellurium Elemental Solid and Microcrystals J. Phys. Chem. Lett. 2019, 10, 15, 4303–4309
[7] Midwavelength Infrared Colloidal Nanowire Laser J. Phys. Chem. Lett. 2022, 13, 6, 1431–1437