seminars

Electronic doping in colloidal semiconductor nanocrystals

Physical and Analytical Chemistry Seminar

Lecturer: Joanna Dehnel

Date:
03-03 Sep 2019

Location: Faculty Seminar Room

Abstract:
Colloidal semiconductor nanocrystals (NCs) are known from their tunable photo-physical properties by variation of size, shape and composition. Last decade studies paid special attention for incorporating of isovalent magnetic ions (e.g. Mn2+) in II–VI NCs which influence their magneto-optical properties without introducing an additional charge into the system.
Recently, research interest has shifted toward incorporation of heterovalent impurities, with respect to the cations sub-lattice commonly called electronic doping. Their insertion changes the overall charge within the host compound, resulting in p- or n- type doping depending on their coordination state and enhance their performance of optical and electronical properties.
An emerging electronic dopant in II-VI NCs is silver (Ag), whose incorporation as Ag+ impurities leads to the introduction of the intragap deep acceptor level which capture the conduction band electron resulting in a Stokes-shifted emission.
In this presentation, I will review the recent synthesis development methods to introduce Ag+ to the host CdSe NCs and focus on investigation of their optical and electrical properties.

References:

[1] Tunable and Efficient Red to Near-Infrared Photoluminescence by Synergistic Exploitation of Core and Surface Silver Doping of CdSe Nanoplatelet. Chem. Mater. 2019, 31, 1450-1459.

[2] Sahu, A.; Kang, M. S.; Kompch, A.; Notthoff, C.; Wills, A. W.; Deng, D.; Winterer, M.; Frisbie, C. D.; Norris, D. J. Electronic Impurity Doping in CdSe Nanocrystals. Nano Lett. 2012, 12, 2587−2594.

[3] Heterovalent Doping in Colloidal Semiconductor Nanocrystals: Cation-Exchange-Enabled New Accesses to Tuning Dopant Luminescence and Electronic Impurities. J.Phys.Chem.Lett. 2017, 8, 4943-4953.

[4] Liu, J.; Zhao, Q.; Liu, J. L.; Wu, Y. S.; Cheng, Y.; Ji, M. W.; Wang, S. G.; Zhang, J. T.; et al. Heterovalent-Doping-Enabled Efficient Dopant Luminescence and Controllable Electronic Impurity Via a New Strategy of Preparing II−VI Nanocrystals. Adv. Mater. 2015, 27, 2753−2761.

[5] Pinchetti, V.; Excitonic Pathway to Photoinduced Magnetism in Colloidal Nanocrystals with Nonmagnetic Dopants. Nat. Nanotechnol. 2018, 13, 145−151.

[6] Chikan, V. Challenges and Prospects of Electronic Doping of Colloidal Quantum Dots: Case Study of CdSe. J. Phys. Chem. Lett. 2011, 2, 2783−2789