seminars

Synthesis and Characterization of Narrow Bandgap Colloidal Nanocrystals and All-Inorganic Perovskites with Magnetic Dopant

Physical and Analytical Chemistry Seminar

Lecturer: Arthur Shapiro

Date:
27-27 Aug 2019 @ 15:30

Location: Faculty Seminar Room

Abstract:

In the last decade, there has been greatly expended interest in narrow bandgap materials which have a comparatively small bandgap with respect to silicon, which makes them the material of choice for many applications in the infrared (IR) spectral regime.

 

Particularly, Lead chalcogenide colloidal quantum dots have raised scientific and technological interest due to their optical tunability in the IR spectral regime. They attract a lot of scientific attention for fundamental studies of strongly confined quantum systems due to their parameters, such as the large effective Bohr radius. The limited chemical stability of lead chalcogenides prevents a study of their properties under ambient conditions and technological implementation. Therefore, the achievement of tunable optical properties across a wide spectral range, along with an efficient surface passivation of lead chalcogenide (PbSe) colloidal quantum dots (CQDs), has significant importance for scientific research and for technological applications. Two comprehensive pathways to tune optical activities of PbSe CQDs in the near-ir and the short-wave ir ranges are described. Although, it is beneficial to work with lead chalcogenides CQDs, lead is a toxic material. Thus, alternatives for future work must be proposed, such as tin chalcogenides. However, their poor chemical and spectral stability has impeded practical applications. The present work explored the mechanism for formation of new nanostructures, SnTe/PbTe/SnO2, with a core/shell/shell heterostructure architecture, governed by the Kirkendall effect.

Separate project will be presented, showing a novel dynamic cation exchange driven by an anion exchange procedure which was used for incorporating Ni dopants into the Pb-site of CsPbBr3 and CsPb(BrCl)3 perovskite nanocrystals under ambient conditions.

 

  1. Shapiro, A. †; Heindl, M. †; Horani, F.; Dahan, M.; Amouyal, Y.; Lifshitz, E., Ni Doping in CsPbX3 Nanocrystals via Post-Synthesis Anion-Cation Co-Exchange. The Journal of Physical Chemistry Letters 2019, Under Review.
  2. Shapiro, A. †; Jang, Y. †; Horani, F.; Kauffmann, Y.; Lifshitz, E., The Kirkendall effect: main growth mechanism for a new SnTe/PbTe/SnO2 nano-heterostructure. Chemistry of Materials 2018, 30 (9), 3141-3149.
  3. Shapiro, A. †; Jang, Y. †; Rubin-Brusilovski, A.; Budniak, A. K.; Horani, F.; Sashchiuk, A.; Lifshitz, E., Tuning Optical Activity of IV–VI Colloidal Quantum Dots in the Short-Wave Infrared (SWIR) Spectral Regime. Chemistry of Materials 2016, 28 (17), 6409-6416.