News

11/7/2017
​Intrinsic Lead Ion Emissions in Zero-Dimensional Cs4PbBr6 Nanocrystals
J. Yin, Y. Zhang, A. Bruno, C. Soci, O.M. Bakr, J.-L. Brédas, O.F. Mohammed
ACS Energy Letters, 2, pp 2805–2811
10/25/2017
​​Room-temperature Engineering of All-inorganic Perovskite Nanocrsytals with Different Dimensionalities
H. Yang, Y. Zhang, J. Pan, J. Yin, O.M. Bakr, O.F. Mohammed
Chemistry of Materials, Just Accepted manuscript
5/28/2017
Perovskite solar cells: Shedding light on film crystallization
Osman M. Bakr, Omar F. Mohammed
Nature Materials 16, 601–602 (2017)​​
5/21/2017
Spatiotemporal Observation of Electron-Impact Dynamics in Photovoltaic Materials Using 4D Electron Microscopy
Basamat S. Shaheen, Jingya Sun, Ding-Shyue Yang, and Omar F. Mo
J. Phys. Chem. Lett. (2017)
3/24/2017
​Powering up perovskite photoresponse
Osman M. Bakr, Omar F. Mohammed
Science Vol. 355, Issue 6331, pp. 1260-1261
2/12/2017
Double Charged Surface Layers in Lead Halide Perovskite Crystals
Smritakshi P. Sarmah, Victor M. Burlakov, Emre Yengel, Banavoth Murali, Erkki Alarousu, Ahmed M. El-Zohry, Chen Yang, Mohd S. Alias, Ayan A. Zhumekenov, Makhsud I. Saidaminov, Namchul Cho, Nimer Wehbe, Somak Mitra, Idris Ajia, Sukumar Dey, Ahmed E. Mansour, Maged Abdelsamie, Aram Amassian, Iman S. Roqan, Boon S. Ooi, Alain Goriely, Osman M. Bakr, and Omar F. Mohammed
Nano Lett., Article ASAP
1/1/2017
​Engineering-Interfacial Charge Transfer in CsPbBr3 Perovskite Nanocrystals by Heterovalent Doping
Raihana Begum, Manas R Parida, Ahmed L. Abdelhady, Banavoth Murali, Noktan Alyami, Ghada H. Ahmed, Mohamed Nejib Hedhili, Osman M. Bakr, and Omar F. Mohammed
J. Am. Chem. Soc., Just Accepted Manuscript
1/1/2017
Temperature-Induced Lattice Relaxation of Perovskite Crystal Enhances Optoelectronic Properties and Solar Cell Performance
Banavoth Murali, Emre Yengel, Wei Peng, Zhijie Chen, Mohd S. Alias, Erkki Alarousu, Boon S. Ooi, Victor Burlakov, Alain Goriely, Mohamed Eddaoudi, Osman M. Bakr, and Omar F. Mohammed
J. Phys. Chem. Lett., 2017, 8, pp 137–143
5/27/2016
​Real-space Mapping of Surface Trap States in CIGSe Nanocrystals using 4D Electron Microscopy
Riya Bose, Ashok Bera, Manas R Parida, Aniruddha Adhikari, Basamat S. Shaheen, Erkki Alarousu, Jingya Sun, Tom Wu, Osman M. Bakr, Omar F. Mohammed
Nano Lett., Just Accepted Manuscript, (2016)
3/15/2016
​Real-space Visualization of Energy Loss and Carrier diffusion in Nanowire Array using Four-Dimensional Electron Microscopy
Riya Bose, Jingya Sun,  Jafar I. Khan, Basamat S. Shaheen, Aniruddha Adhikari, Tien Khee Ng, V. M. Burlakov, Manas R. Parida, Davide Priante, A. Goriely, Boon S. Ooi, Osman M. Bakr, Omar F. Mohammed
Advanced Materials, Article in Press, (2016)
3/13/2016
​Remarkably high conversion efficiency of inverted bulk heterojunction solar cells: from ultrafast laser spectroscopy and electron microscopy to device fabrication and optimization
Qana A. Alsulami, Banavoth Murali, Y. Alsinan, Manas R. Parida, Shawkat M. Aly, Omar F. Mohammed
Advanced Energy Materials, Article in Press, (2016)
3/3/2016
​Mapping Carrier Dynamics on Material Surfaces in Space and Time using Scanning Ultrafast Electron Microscopy
Jingya Sun, Aniruddha Adhikari, Basamat S. Shaheen, Haoze Yang, and Omar F. Mohammed
J. Phys. Chem. Lett., 7(6), pp 985-994, (2016)
2/23/2016
​Enhanced Optoelectronic Performance of a Passivated Nanowire-based Device: Key Information from Real-space Imaging using 4D Electron Microscopy
Jafar I. Khan, Aniruddha Adhikari, Jingya Sun, Davide Priante, Riya Bose, Basamat S. Shaheen, Tien Khee Ng, Chao Zhao, Osman M. Bakr, Boon S. Ooi, Omar F. Mohammed
Small, 12(7), pp 2313-2320, (2016)
2/22/2016
​Triplet excited state properties in variable gap π-conjugated donor-acceptor-donor chromophores
Seda Cekli, Russell W. Winkel, Erkki Alarousu, Omar F. Mohammed, Kirk S Schanze
Chem. Sci., Accepted Manuscript (2016)
1/1/2016
Ultrafast static and diffusion-controlled electron transfer at Ag29 nanocluster/molecular acceptor interfaces
Omar F. Mohammed, Shawkat Aly, Lina G. AbdulHalim, Tabot Besong, Giada Soldan, and Osman M. Bakr
Nanoscale, 8, pp 5412-5416, (2016) ​​
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12/1/2015
Air-stable surface-passivated perovskite quantum dots for ultra-robust, single- and two-photon-induced amplified spontaneous emission
Jun Pan, Smritakshi P. Sarmah, Banavoth Murali, Ibrahim Dursun, Wei Peng, Manas R Parida, Jiakai Liu, Lutfan Sinatra, Noktan Alyami, Chao Zhao, Erkki Alarousu, Tien Khee Khee Ng, Boon S. Ooi, Osman M. Bakr, and Omar F. Mohammed
J. Phys. Chem. Lett., 6(24), pp 5027-5033, (2015)​
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11/12/2015
Templated atom-precise galvanic synthesis and structure elucidation of a [Ag24Au(SR)18]− nanocluster
Megalamane S. Bootharaju, Chakra P. Joshi, Manas R. Parida, Omar F. Mohammed, Osman M. Bakr
Angewandte Chemie, 55(3), pp 922–926, (2016)​
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10/15/2015
Overcoming the cut-off charge transfer bandgaps at the Pbs quantum dot interface
Ala’a O. El-Ballouli, Erkki Alarousu, Ahmad R. Kirmani, Aram Amassian, Osman M. Bakr, and Omar F. Mohammed
Advanced Functional Materials, 
25(48), pp 7435-7441, (2015)
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9/14/2015
Real-space imaging of carrier dynamics of materials surfaces by second-generation four-dimensional scanning ultrafast electron microscopy
Jingya Sun, Vasily A. Melnikov, Jafar I. Khan, and Omar F. Mohammed
J. Phys. Chem. Lett., 6(19), pp 3884–3890, (2015)
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8/13/2015
The impact of grain alignment of the electron transporting layer on the performance of inverted bulk heterojunction solar cells
Banavoth Murali, Abdulrahman El Labban, Jessica Eid, Erkki Alarousu, Dong Shi, Qiang Zhang, Xixiang Zhang, Osman M. Bakr, and Omar F. Mohammed  
Small, 11(39), pp 5272-5279, (2015)​
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7/6/2015
High-quality bulk hybrid perovskite single crystals within minutes by inverse temperature crystallization
M.I. Saidaminov, A.L. Abdelhady, B. Murali, E. Alarousu, V.M. Burlakov, W. Peng, I. Dursun, L. Wang, Y. He, G. Maculan, A. Goriely, T. Wu, O.F. Mohammed & O.M. Bakr 
Nature Communications 6, 7586, (2015)
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6/25/2015
Ultrafast excited-state dynamics of diketopyrrolopyrrole (DPP)-based materials: static versus diffusion-controlled electron transfer process
Q.A. Alsulami, S.M. Aly, S. Goswami, E. Alarousu, A. Usman, K.S. Schanze, and O.F. Mohammed
J. Phys. Chem. C,119 (28), pp 15919–15925, (2015)
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4/15/2015
Ultrafast pump-probe reflectance spectroscopy: Why sodium makes Cu(In,Ga)Se2 solar cells better
Jessica Eid, Anwar Usman, Issam Gereige, Jeroen Van Duren, Vadim Lyssenko, Karl Leo, Omar F. Mohammed 
Solar Energy Materials and Solar Cells, 140, pp 33–37, (2015)
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3/31/2015
Quantum Confinement-Tunable Intersystem Crossing and Triplet State Lifetime of Cationic Porphyrin-CdTe Quantum Dot Nano-assemblies
Omar F. Mohammed, Ghada Ahmed, Shawkat Aly, Anwar Usman, Mohamed Eita and Vasily Melnikov 
Chem. Commun., 
51, pp 8010-8013, (2015)​​
2/12/2015
Molecular-structure control of ultrafast electron injection at cationic porphyrin-CdTe quantum dot interfaces
Shawkat M. Aly , Ghada H. Ahmed , Basamat S. Shaheen , Jingya Sun , and Omar F. Mohammed 
J. Phys. Chem. Lett., 6 (5), pp 791–795, (2015) 
2/6/2015
Photoinduced triplet-state electron transfer of platinum porphyrin: A one-step direct method for sensing iodide to an unprecedented detection limit
Dilshad Masih, Shawkat M. Aly, Erkki Alarousu, and Omar F. Mohammed.
J. Mater. Chem. A, 3, pp 6733-6738, (2015)​
1/30/2015
Low trap-state density and long carrier diffusion in organolead trihalide perovskite single crystals
Dong Shi, Valerio Adinolfi, Riccardo Comin, Mingjian Yuan, Erkki Alarousu, Andrei Buin, Yin Chen, Sjoerd Hoogland, Alexander Rothenberger, Khabiboulakh Katsiev, Yaroslav Losovyj, Xin Zhang, Peter A. Dowben, Omar F. Mohammed, Edward H. Sargent, Osman M. Bakr  
Science, 347(6221), pp 519-522, (2015)
1/24/2015
Tunable-Photophysical Processes of Porphyrin Macrocycles on the Surface of ZnO Nanoparticles.
Manas R. Parida, Shawkat M. Aly, Erkki Alarousu, and Omar F. Mohammed.
J. Phys. Chem. C, 119 (5), pp 2614–2621, (2015).
1/22/2015
Ambient Layer-by-Layer ZnO Assembly for Highly Efficient Polymer Bulk Heterojunction Solar Cells.
Mohamed Eita, Abdulrahman El Labban, Federico Cruciani, Anwar Usman, Pierre M. Beaujuge and Omar F. Mohammed.
 Advanced Functional Materials, 25(10), pp 1558–1564, (2015)​
1/20/2015
Direct Femtosecond Observation of Charge Carrier Recombination in Ternary Semiconductor Nanocrystals: The Effect of Composition and Shelling.
Riya Bose, Ghada H. Ahmed, Erkki Alarousu, Manas R Parida, Ahmed Lutfi Abdelhady, Osman M. Bakr, and Omar F. Mohammed.
J. Phys. Chem. C, 119 (6), pp 3439–3446, (2015)
1/1/2015

Solvent-Dependent Excited-State Hydrogen Transfer and Intersystem Crossing in 2-(2’-Hydroxyphenyl)-Benzothiazole. Shawkat M. Aly, Anwar Usman, Maytham AlZayer, Ghada A. Hamdi, Erkki Alarousu, and Omar F. Mohammed. J. Phys. Chem. B, 119 (6), pp 2596–2603, (2015)

11/20/2014
Perovskite Oxide SrTiO3 as an Efficient Electron Transporter for Hybrid Perovskite Solar Cells.
Ashok Bera, Kewei Wu, Arif Sheikh, Erkki Alarousu, Omar F. Mohammed, and Tom Wu.
J. Phys. Chem. C, 118(49), pp 28494-28501, (2014)
9/17/2014

Ultrafast Photoinduced Electron Transfer in a pi-Conjugated Oligomer/Porphyrin Complex.

Shawkat M. Aly, Subhadip Goswami, Qana A. Alsulami, Kirk S. Schanze and Omar F. Mohammed.

The Journal of Physical Chemistry Letters. 5(19), pp 3386-3390, (2014)

7/20/2014
Ultrafast Electron Injection at the Cationic Porphyrin-Graphene Interface Assisted by Molecular Flattening.
Shawkat Aly, Manas Parida, Erkki Alarousu, and Omar F. Mohammed.
Chem. Commun., 50(72), pp 10452-10455, (2014).
7/3/2014

Impact of Metal Ions in Porphyrin-Based Applied Materials for Visible-Light Photocatalysis: Key Information from Ultrafast Electronic Spectroscopy. Prasenjit Kar, Samim Sardar, Erkki Alarousu, Jingya Sun, Zaki S. Seddigi, Saleh A. Ahmed, Ekram Y. Danish, Omar F. Mohammed, and Samir Kumar Pal. Chemistry - A European Journal, 20, pp 10475-10483, (2014).

6/12/2014
Ultrafast Carrier Trapping of a Metal-doped Titanium Dioxide Semiconductor Revealed by Femtosecond Transient Absorption Spectroscopy.
Jingya Sun, Yang Yang, Jafar I. Khan, Erkki Alarousu, Zaibing Guo, Xixiang Zhang, Qiang Zhang, and Omar F. Mohammed.
ACS Applied Materials & Interfaces, 6(13), pp 10022-10027, (2014)
5/27/2014

Solar energy is all about efficiency. To challenge fossil fuels, solar cells must convert more sunshine into electricity, at lower cost, than they can do today.

5/22/2014
Remarkable Fluorescence Enhancement versus Complex Formation of Cationic Porphyrins on the Surface of ZnO Nanoparticles.

Shawkat M. B. Aly, Mohamed Eita, Jafar I. Khan, Erkki Alarousu, and Omar F. Mohammed. The Journal of Physical Chemistry C, 118(23), pp 12154-12161, (2014)

5/21/2014
Excited-State Intramolecular Hydrogen Transfer (ESIHT) of 1,8-Dihydroxy-9,10-anthraquinone (DHAQ) Characterized by Ultrafast Electronic and Vibrational Spectroscopy and Computational Modeling. Omar F. Mohammed, Dequan Xiao, Victor S. Batista, and Erik T. J. Nibbering. The Journal of Physical Chemistry A, 118 (17), pp 3090–3099, (2014)
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3/1/2014

Real-Time Observation of Ultrafast Intraband Relaxation and Exciton Multiplication in PbS Quantum Dots. Ala’a O. El-Ballouli, Erkki Alarousu, Anwar Usman, Jun Pan, Osman M. Bakr, and Omar F. Mohammed. ACS Photonics, 1 (3), pp 285–292, (2014)

2/12/2014

Quantum Confinement-Tunable Ultrafast Charge Transfer at the PbS Quantum Dot and Phenyl-C61-butyric Acid Methyl Ester Interface.

Ala’a O. El-Ballouli, Erkki Alarousu, Marco Bernardi, Shawkat M. Aly, Alec P. Lagrow, Osman M. Bakr, and Omar F. Mohammed.

Journal of the American Chemical Society, 136 (19), pp 6952–6959, (2014)


1/28/2014

Generation of Multiple Excitons in Ag2S Quantum Dots: Single High-Energy versus Multiple-Photon Excitation.

Jingya Sun, Weili Yu, Anwar Usman, Tayirjan T. Isimjan, Silvano DGobbo, Erkki Alarousu, Kazuhiro Takanabe, and Omar F. Mohammed.

The Journal of Physical Chemistry Letters, 5 (4), pp 659–665, (2014)