member-academic-staff
Efrat Lifshitz

Efrat Lifshitz

Professor
+972-4-829-3645/+972-4-8293987
130 mm
Nanoscience and nanotechnology; Synthesis, structural and physical characterizations of II-VI and IV-VI quantum dot, rots, wires and platelets, core/shell derivatives, magnetically doped nanostructures, perovskites and single slabs of transition metal chalcogenides; Optical, magneto-optical characterization of ensemble and single nanostructures; Implementation as Q-switches, lasers, solar cells and biological devices.

Semicondutor nanostructures and dedicated magneto-optical methodologies
Prof. Efrat Lifshitz is among the poineers who initiated an exciting revolution in the synthesis of nanoscaled semiconductor materials. She has developed and utilized complex magneto-optical methodologies, resulting in a tremendous contribution to the study of tailor-made physical properties of nano-scaled materials. Prof. Lifshitz’s program has developed progressively from two-dimensional materials, such as layered semiconductors and their intercalation compounds, to one-dimensional and zero-dimensional materials, including colloidal quantum dots, cubes, wires, rods, ribbons and multi-pods (see Figure 1).

The low dimensional materials represent a class of luminescent chromophores with quantizePicture1newd electronic states, and tunable intense optical transitions that vary with the material’s size, shape and composition.

During the past decade, the Lifshitz group has focused on the development of nanostructures with optical activity in the near infrared spectral regime. Based on the group’s accumulated knowledge and skills, they have developed alloyed nanostructures, with unique photochemical stability, overcoming well known obstacles such as spectral instabilities (so-called fluorescence blinking). The materials developed exhibit potential as active components in telecommunication, gain devices, display devices, photodetectors, optical switches and filters, spintronics, and biological tagging. The following sections outline briefly the development of materials (past and current), methodologies, applications and theoretical models.

Materials: Nanostructures were produced either by colloidal chemical procedures or by vapor transport growth: (a) Colloidal quantum dots, rodes, wires, platelets of CdSe, CdTe, PbSe, PbS coated with organic ligands or by epitaxial layer of another semiconductor, known also as core-shell structures, such as PbSe/PbS, CdSe/CdS, CdTe/CdSe; (b) Colloidal nanostructures with alloyed composition, such as PbSexS1-x or PbSe/PbSexS1-x core-shell hetero-structures; (c) Mn+2 doped core/shell nano-structures, placing dopants either at the core or at the shell; (d) Layered semiconductors from transition metal dichalcogenides or iodides (SnS2, PbI2, Bi2I3) and metal phosphore-tri-chalcogenides (MPX3, M=Mn, Fe, Ni, Mg, Cd); (e) Chemically prepared Perovskites dot, rods and platelets; (f) Spray prepared nanostructures; (g), Metallic/magnetic nanostructures (g- Fe2O3); and their complex structures with CQDs; (h) Ordered or disordered packing of nanostructures, or dispersion with extremely high dilution. Variety of materials were implemented for various applications in collaboration with industry or academic institude to form, eye-safe lasers, solar cells, up-conversion and biological tags.

 

Methodologies: Prof. Efrat Lifshitz developed notable expertise in several distinctive methodologies combining magnetic resonance, cyclotron resonance, magnetic polarization, microwave absorption and optical spectroscopy, supplying information not revealed by conventional techniques, such as angular momentum of electronic states,Picture2new
g-factors, exchange interaction, Zeeman interaction, diamagnetic shift, crystal field and Rashba effects, all possessing considerable importance in understanding the physical properties of nano-scaled materials. These methodologies include the following: (a) Optically detected magnetic resonance (ODMR); (b) Microwave and thermal modulated photoluminescence; (c) Optically detected cyclotron resonance; (d) Circular polarized photoluminescence in the presence of an external magnetic field; (e) Magneto-optical confocal microscopy, when detecting the photoluminescence of isolated single nanostructure under the influence of an external magnetic field; (f) Atomic force microscopy combined with confocal microscopy for the manipulation and detection of a single nanostructure; (g) Confocal microscopy combined with magnetic resonance measurement at the excited state (viz, optically detected magentic resonance of an isolated single nanostructure). Experimental set-up or/and representative results are depicted in Figure 2.

ODMRRRRR

Theory: The electronic band structure calculations of core and core/shell quantum dot and rods were calculated, using an effective mass approximation method. A distinct treatment beyond state-of-the-art was included, considering strain effects, their relaxation by a soft boundary and graded composition around core/shell interface, finite external barrier and dielectric confinement. Later, Coulomb interactions, exchange interactions, cross section for absorption and complex Auger processes, (in collaboration with Prof. A. Efros, USA), spin alignment and polarization effect were calculated and compared with experimental results. Other recent studies included electrical conductivity in double quantum dots, emphasizing the influence of the inter-dot distance created by the capping ligands and their influence on the connectivity properties, showing exceptional phenomena such as induced recoil or negative resistance induced by application of charge or voltage (in collaboration with Prof. U. Peskin, Technion, Israel). The theoretical tools are implemented now a days in various current projects under consideration.

 

Post Doc: University of Michigan and at the Weizmann Institute of Science, 1985-1989
Ph.D: University of Michigan, USA, 1984
B.Sc: Hebrew University in Jerusalem, 1979

Curriculum Vitae

list of publications 2000-2016

Awards
The 2016 Israel Vacuum Society Excellence Award for Research(2016); UK-Israel Lectureship Award, Oxford University (2015); Tenne Family Prize in memory of Lea Tenne for Nanoscale Sciences, awarded by the Israel Chemical Society (2015); External Senior Fellow at the Freiburg Institute of Advanced Studies (2015)

2003 – Outstanding Women in Science and Technology, Haifa Municipality.
2000 – David Ben-Aharon for Achievements in Science, Technion.
1993-1996 – Theodore and Mina Bargman Lectureship, Technion.

Selected Publications

1.  Maikov, G. I.; Vaxenburg, R.; Sashchiuk, A.; Lifshitz, E. “Composition-Tunable Optical Properties of Colloidal IV-VI Quantum Dots, Composed of Core/Shell Heterostructures with Alloy Components”, ACS Nano (2010), 4(11) ASAP.
2.  Grinbom, G.; Saraf, M.; Sagy, S.; Bartnik, A.; Wise, F.; Lifshitz, E. “Electronic structure of PbSe/PbS core-shell NCs obtained by STS measurement”, Phys. Rev. B (2010), 81, 245301.
3.  Etgar, L.; Nakhmani, A.; Tannenbaum, A.; Lifshitz, E.; Tannenbaum, R. “Trajectory control of PbSe–γ-Fe2O3 nanoplatforms under viscous flow and an external magnetic field”, Nanotechnology (2010), 21, 175702.
4.  Osovsky, R.; Cheskis, D.; Kloper, V.; Sashchiuk, A.; Lifshitz, E.,”Continuous wave pumping of multiexcitons in a single blinking free colloidal quantum dots”, Phys. Rev. Lett. (2009), 102, 197401.
5.  Lamhot Y, Barak A, Rotschild C, Segev, Saraf M, Lifshitz E, Marmur A, El-Ganainy “Optical control of thermocapillary effects in complex nanofluids”, Phys Rev Lett. (2009), 103(26):264503.
6.  Kigel, A.; Brumer, M.; Maikov, G.; Sashchiuk, A.; Lifshitz, E., “Thermal activation of photoluminescence in PbSe nanocrystals”, SMALL 5, (2009), 14, 1675–1681.
7.  Etgar L.; Assaraf Y. G.; G. Leitus, G.; Fradkin L.; Tannenbaum R; Lifshitz E., -Fe2O3 nanoparticlesg”Optical and magnetic properties of PbSe quantum dots – conjugate structures”, ChemPhysChem (2009), 10(13), 2235-2241.
8.  Bashouti, M.; Lifshitz, E., “Colloidal PbS Ribbons, Wires, Octa-pods and Hollowed Cubes”, Inorganic Chemistry (2008) 47(2), 678-682.
9.  Amirav, L.; Lifshitz, E. “Thermospray: A Method for Producing High Quality Semiconductor Nanocrystals”, J. Phys. Chem. C (2008), 112(34), 13105-13113.
10.  Bartnik, A. C.; Wise, F. W.; Kigel, A.; Lifshitz, E. “Electronic structure of PbSe/PbS core-shell quantum dots”, Phys. Rev. B (2007) 75, 245424.
11.  Kloper, V.; Osovsky, R; Kolny-Olesiak, J.; Sashchiuk, A.; Lifshitz, E., “The growth of CdTe nanocrystals using in situ formed Cd0 crystalline particles”, J. Phys. Chem. C (2007) 111(36); 10336-10341.
12.  Lifshitz, E.; Brumer, M.; Kigel, A.; Sashchiuk, A.; Bashouti, M.; Sirota, M.; Galun, E.; Burshtein, Z.; Le Quang, A. Q.; Ledoux-Rak, I. and Zyss, J., “Air-stable PbSe/PbS and PbSe/PbSexS1-x core-shell nanocrystals quantum dots and their applications”, J. Phys. Chem. B (2006) 110(50); 25356-25365.
13.  Lifshitz, E.; Fradkin, L.; Glozman, A.; Langof, L., “Optically detected magnetic resonance studies of colloidal semiconductor nanocrystals”, Annual Review of Physical Chemistry (2004) 55, 509-557 (Invited Review).

Full List of Publications

 

 

Name Email Room Phone
Gary Zaiats
  sgaryz@technion.ac.il 212 3750
Roman Vaxenburg
212 3750
Richard Capek
  capek@technion.ac.il 212 3750
Natan Grumbach
  nathangr@technion.ac.il 212 3750
Aldona Sashchiuk
  chaldona@technion.ac.il 314g/212 5644/3750
Arthur Shapiro
  sarthur@technion.ac.il 212 3750
Inbal Hesseg
  inbalhes@technion.ac.il 212 3756
Orit Livni
  oritli@technion.ac.il 145 (solid state) 2053
Itay Meir
  itaymeir@campus.technion.ac.il 65 (solid state) 3469
Yahel Barak
  yahelbarak@technion.ac.il 2053
Alyssa Kostadinov
  salyssak@campus.technion.ac.il 58 (Solid state) 3938
Adam Krzysztof Budniak
  adam.budniak@technion.ac.il 212 3750
Faris Horani
  h.faris@technion.ac.il 212 3750
Azhar Abu Hariri
  sazharh@campus.technion.ac.il 212 3750
Joanna Dehnel
  joannadehnel@technion.ac.il 212 3750

 

 

 

 

 

 

http://schulich.technion.ac.il/files/researchers_cv/cvEfratLifshitz.pdf