BEGIN:VCALENDAR
VERSION:2.0
PRODID:https://murmitoyen.com/events/vanille/udem/
X-WR-TIMEZONE:America/Montreal
BEGIN:VEVENT
UID:69db2d3624e76
DTSTAMP:20260412T012718
DTSTART:20171127T113000
SEQUENCE:0
TRANSP:OPAQUE
DTEND:20171127T123000
URL:https://murmitoyen.com/events/vanille/udem/detail/786791-carrier-dynami
 cs-using-ultrafast-spectroscopy-and-electron-microscopy
LOCATION:Université de Montréal - Pavillon J.-Armand-Bombardier\, 5155\, 
 chemin de la rampe \, Montréal\, QC\, Canada\, H3T 2B2
SUMMARY:Carrier Dynamics using Ultrafast Spectroscopy and Electron Microsco
 py
DESCRIPTION:Titre completMapping Charge Carrier Dynamics in Real-space and 
 Time on Semiconductor Material Surfaces and Interfaces using Ultrafast Spe
 ctroscopy and Four-dimensional Electron MicroscopyOmar MohammedSolar and P
 hotovoltaics Engineering Research Center (SPERC)Division of Physical Scien
 ces and Engineering (PSE)King Abdullah University of Science and Technolog
 y (KAUST)
\nAbstract: Understanding light-triggered charge carrier dynamic
 s on photovoltaic-material surfaces and at interfaces has been a key eleme
 nt and one of the major challenges for the development of real-world energ
 y devices. For this reason\, studying charge carrier dynamics at photoacti
 ve material surfaces and interfaces have been among the most active areas 
 of research in the last decade [1-4]. However\, the ability to access carr
 ier dynamics selectively on material surfaces with high spatial and tempor
 al control in a photo-induced reaction is a particularly challenging task 
 that can only be achieved by applying four-dimensional (4D) ultrafast elec
 tron microscopy (4D UEM) along with time-resolved laser spectroscopy. For 
 this purpose\, we established and developed the second generation 4D S-UEM
  and demonstrate the ability to take time-resolved secondary electrons ima
 ges (snapshots) of material surfaces with 650 fs and ~ 4 nm temporal and s
 patial resolutions\, respectively. In this method\, the surface of the pho
 toactive materials is excited by a clocking optical pulse and the photo-in
 duced changes will be imaged using a pulsed primary electron beam as a pro
 be pulse\, generating secondary electrons\, which are emitted from the top
  surface of the material in a manner that is extremely sensitive to the lo
 calization of the electron and hole on the surface and at the donor-accept
 or interfaces. This method provides direct and controllable ultrafast dyna
 mical information in many photoactive materials commonly used in solar cel
 ls and photo-catalysis. For instance\, we have clearly demonstrated in spa
 ce and time how the surface morphology\, surface passivation\, thickness o
 f the absorber layer\, grains\, surface defects and nanostructured feature
 s can significantly impact the overall dynamical processes on the surface 
 of absorber layers including nanomaterials and single crystals [5-8]. Fina
 lly\, charge carrier dynamics in semiconductor quantum dots and perovskite
  single crystal using femtosecond laser spectroscopy will be also presente
 d and discussed.
\nReferences
\n
\nO. M. Bakr\, O. F. Mohammed.\, Science 
 355\, 1260 (2017).
\nA. O. El-Ballouli\, E. Alarousu\, M. Bernardi\, S. M.
  Aly\, A. P. Lagrow\, O. M. Bakr\, O. F. Mohammed.\, J. Am. Chem. Soc. 136
 \, 6952 (2014).
\nR. Begum\, M. R. Parida\, A. L. Abdelhady\, B. Murali\, 
 N. Alyami\, G. H. Ahmed\, M. N. Hedhili\, O. M. Bakr\, and O. F. Mohammed.
 \, J. Am. Chem. Soc. 139\, 731 (2017).
\nO. F. Mohammed\, D.-S. Yang\, S. 
 Pal\, A. H. Zewail\, J. Am. Chem. Soc. 133\, 7708 (2011).
\nJ. Sun\, V. A.
  Melnikov\, J. I. Khan\, O. F. Mohammed\, J. Phys. Chem. Lett. 6\, 3884 (2
 015).
\nR. Bose\, J. Sun\, J. I. Khan\, B. S. Shaheen\, A. Adhikari\, T. K
 . Ng\, V. M. Burlakov\, M. P. Parida\, D. Priante\, A. Goriely\, B. S. Ooi
 \, O. M. Bakr\, O. F. Mohammed\, Adv. Mater. 28\, 5106 (2016).
\nB. S. Sha
 heen\, J. Sun\, D-S Yang\, and O. F. Mohammed\, J. Phys. Chem. Lett. 8\, 2
 455 (2017).
\nR. Bose\, A. Bera\, M. R. Parida\, A. Adhikari\, B. S. Shahe
 en\, E. Alarousu\, J. Sun\, T. Wu\, O. M. Bakr\, O. F. Mohammed\, Nano Let
 t. 16\, 4417 (2016).
\n
\nBio:
\nEducation
\n
\nPh.D.\, Physical Chemistry
 \, Humboldt University of Berlin\, Germany\, 2006
\nM.Sc.\, Chemistry\, As
 siut University\, Egypt\, 1999
\nB.Sc.\, Chemistry\, Assiut University\, E
 gypt\, 1995
\n
\nProfessional Profile
\n
\n2012–present: Assistant Profe
 ssor\, Chemical Sciences\, KAUST\, Saudi Arabia
\n2008–2012: Senior Rese
 arch Associate\, California Institute of Technology\, USA
\n2007–2008: P
 ostdoctoral Associate\, RIKEN (Institute of Chemical and Physical Research
 )\, Japan
\n2006–2007: Postdoctoral Associate\, University of Geneva\, S
 witzerland
\n2002-2006: Graduate Studies in Chemistry\, MBI\, Berlin\, Ger
 many
\n
\nAwards
\n
\nLong term fellowship\, Max-Born Institute\, Berlin\,
  Germany
\nPost-doctoral Fellowship (JSPS fellowship) & Special post-docto
 ral researcher (RIKEN fellowship)\, RIKEN\, Japan
\nDistinguished scholar 
 award from Arab Fund for Economic and Social Development\, Kuwait
\nThe St
 ate Prize in Basic Sciences\, Egypt
\n
\nFor more information\, you can co
 nsult this web page.
\nCette conférence est présentée par le RQMP Ver
 sant Nord du Département de physique de l'Université de Montréal et d
 e Génie physique de la Polytechnique.
END:VEVENT
BEGIN:VTIMEZONE
TZID:America/Montreal
X-LIC-LOCATION:America/Montreal
END:VTIMEZONE
END:VCALENDAR