Timothy Atallah

Timothy Luke Atallah

Assistant Professor
Position Type
- Present
Physical and Materials Chemistry

I was born and raised on the island of Cyprus in the Mediterranean Sea; my dad being from Egypt and Lebanon and my mom from central Illinois. From a young age I have enjoyed mixing, tinkering and problem solving so I was drawn to chemistry, physics and math in college in West Michigan. After which I moved to Austin, Texas for graduate school and then moved to New York City to finish graduate school. During graduate school I loved working with lasers as well as technologically relevant materials, thinking about how processes in semiconductors work to result in us having computers, screens, sensors, medical devices, etc… I completed my postdoctoral work before coming to Denison at the University of California in Los Angeles where I worked on developing new spectroscopy methods and understanding materials in the infra-red which are relevant for deep tissue imaging and automated vehicle remote sensing through fog.

What I love about chemistry is it’s really relevant to everything we do, literally almost everything we come into contact and use everyday has been designed by chemists or relates to chemistry: from the paint on our walls, the clothes we wear, our devices, our bodies, our pharmaceuticals, our foods, our energy sources, etc… Even with a basic grasp of concepts we can start to understand the world around us - revealing this wondrous universe made up of atoms, molecules and energy - a wonder I love to share with others and as well as the drive to learn and grow together!

Away from school, my wife and I enjoy cooking and trying new foods, exploring our local communities and hiking outdoors, playing tabletop board/card and computer games, and since COVID-19 I have taken up miniature painting as a stress relief and way to think through things I am working on.

B.Sc. Calvin College, M.Phil., Ph.D. Columbia University

Learning & Teaching

  • Chemistry 131: Principles of Chemistry: Atoms and Molecules
  • Chemistry 343: Intermediate Physical Chemistry



I am interested in developing next generation low-cost semiconductors such as those derived from organic or nanomaterials and uncovering the physical processes that govern these materials when implemented in a device or for photocatalysis (i.e. in the excited states). In the Atallah lab we grow our semiconductors using colloidal wetlab synthesis methods as well as physical vapor transport to sublimate high purity crystals. As a spectroscopist my passion lies in using light to characterize these materials in the excited state: one technique we use picosecond (i.e. one trillionth of second) lasers to characterize how energy and charges will move in these materials once excited as well as the colors of light emitted once excited to learn about where and how the energy is flowing and if there are any parasitic loss channels. We use other spectroscopic methods including polarization anisotropy and Raman to correlate photo-physical/chemical processes with structure and cryogenic measurements to determine how temperature affects these properties.


  • Tenney, S. M; Tan, L. A.; Sonnleitner, M. L.; Sica, A. V.; Shin, A. J.; Ronquillo, R.; Ahmed T.; Atallah, T. L.; Caram J. R. Seeded Growth of Mesoscale Quantum-Confined Semiconductor Nanoplatelets Chem. Mater. 2022, 34, 6048-6056.
  • Deshmukh, A. P; Geue, N.; Bradbury, N. C.; Atallah, T. L.; Chuang, C.; Pengshung, M.; Cao, J.; Sletten, E. M.; Daniel Neuhauser, D.; Caram J. R. Bridging the Gap between H- and J-Aggregates: Classification and Supramolecular Tunability for Excitonic Band Structures in 2-Dimensional Molecular Aggregates Chem. Phys. Rev. 2022, 3, 021401.
  • Chen, P.;* Atallah, T. L.;* Lin, Z.; Wang, P.; Lee, S-J.; Xu, J.; Huang, Z.; Ping, Y.; Huang, Y.; Duan, X.; Caram, J. R.; Duan, X. Approaching the intrinsic exciton physics limit in two-dimensional semiconductor diodes Nature, 2021, 599, 404-410 *Co-First Author
  • Friedman, H. C.; Cosco, E. D.; Atallah, T. L.; Sletten, E. M.; Caram, J. R. Establishing design principles for emissive organic SWIR chromophores from energy gap laws, Chem, 2021, 7, 3359-3376
  • Shin, A. J.; Hossain, A.;† Tenney, S. T; Tan, X.; Tan, L.;† Foley IV, J. J.; Atallah, T. L.;* Caram, J. R.* Dielectric Screening Modulates Nanoplatelet Excitons J. Phys. Chem. Lett. 2020, 12, 4958-4964. *Co-Corresponding Author
  • Cosco, E. D.; Arús, B. A.; Spearman, A. L.; Atallah, T. L.; Leland, O. S.; Bischof, Caram, J. R.; T. S.; Bruns, O. T.; Sletten, E. M. Bright Polymethine Emitters for Multiplexed Shortwave Infrared in Vivo Imaging J. Am. Chem. Soc. 2021, 143, 6836-6846.
  • Wang, Y.; Jia, C.; Fan, Z.; Lin, Z.; Lee, S.-J.; Atallah, T. L.; Caram, J. R.; Huang, Y.; Duan, X. Large-Area Synthesis and Patterning of All-Inorganic Lead Halide Perovskite Thin Films and Heterostructures Nano Lett. 2021, 21, 1451-1460.
  • Guo, H.; Dickerson, C. E.; Shin, A. J.; Zhao, C.; Atallah, T. L.; Caram, J. R.; Campbell, W. C.; Alexandrova, A. N. Surface Chemical Trapping of Optical Cycling Centers Phys. Chem. Chem. Phys. 2021, 23, 211-213.
  • Tenney, S. M.; Vilchez, V.; Sonnleitner, M.; † Huang, C.; † Friedman, H. C.; Shin, A. J.; Deshmukh,A.; Atallah, T. L.; Ithurria S.; Caram, J. R. Mercury Chalcogenide Nanoplatelet-Quantum Dot Heterostructures as a New Class of Continuously Tunable Bright Shortwave Infrared Emitters J. Phys. Chem. Lett. 2020, 11, 3473–3480. Pengshung, M.; Neal, P.; Atallah, T. L.; Kwon, J.; Caram, J. R.; Lopez, S. A.; Sletten, E. M. Silicon Incorporation in Polymethine Dyes Chem. Comm. 2020, 56, 6110-6113.
  • Atallah, T. L.; Sica, A. V.; Shin, A. J.; Friedman, H. C.; Kahrobai, Y. K.; † Caram, J. R. Decay-Associated Fourier Spectroscopy: Visible to Shortwave Infrared Time-Resolved Photoluminescence Spectra J. Phys. Chem. A 2019, 123, 6792-6798.
  • Evans, T. J. S.; Schlaus, A.; Fu, Y.; Zhong, X.; Atallah, T. L.; Spencer, M .S.; Brus, L. E.; Jin, S.; Zhu, X.-Y. Continuous-Wave Lasing in Cesium Lead Bromide Perovskite Nanowires Adv. Opt. Mat. 2018, 6, 1700982. Miyata, K.; Atallah, T. L.; Zhu, X.-Y. Lead Halide Perovskites: Crystal-Liquid Duality, Phonon Glass Electron Crystals, and Large Polaron Formation Sci. Adv. 2017, 3, e1701469.
  • O ’Brien, E. S.; Trinh, M. T.; Kann, R. L.; Chen, J.; Elbaz, G. A.; Masurkar, A.; Atallah, T. L.; Paley, M. V; Patel, N.; Paley, D. W.; Kymissis, I.; Crowther, A. C.; Millis, A. J.; Reichman, D. R.; Zhu, X.; Roy, X. Single-Crystal-to-Single-Crystal Intercalation of a Low-Bandgap Superatomic Crystal Nat. Chem. 2017, 9, 1170-1174.
  • Atallah, T. L.; Wang, J.; Bosch, M.; † Seo, D.; R. Burke, Moneer, O.; Zhu, J.; Theibault, M.; † Brus, L.; Hone, J.; Zhu, X.-Y. Electrostatic Screening of Charged Defects in Monolayer MoS2 J. Phys. Chem. Lett. 2017, 8, 2148-2152.
  • Atallah, T. L.; Gustafsson, M. V; Schmidt, E.; Frisbie, C. D.; Zhu, X.-Y. Charge Saturation and Intrinsic Doping in Electrolyte-Gated Organic Semiconductors J. Phys. Chem. Lett. 2015, 6, 4840–4844. Morris, J. D.; Atallah, T. L.; Park, H.; Ooi, Z.; Dodabalapur, A.; Zhu, X.-Y. Quantifying Space Charge Accumulation in Organic Bulk Heterojunctions by Nonlinear Optical Microscopy Org. Electron. 2013, 14, 3014–3018.
  • Morris, J. D.; Atallah, T. L.; Lombardo, C. J.; Park, H.; Dodabalapur, A.; Zhu, X.-Y. Mapping Electric Field Distributions in Biased Organic Bulk Heterojunctions under Illumination by Nonlinear Optical Microscopy Appl. Phys. Lett. 2013, 102, 33301.
  • Atallah, T. L.; Blankespoor, R. L.; Homan, P.; Hulderman, C.; Samas, B. M.; Van Allsburg, K.; Vrieze, D. C. Substituent Effects on the Amination of Racemic Allyl Carbonates Using Commercially Available Chiral Rhodium Catalysts. Tetrahedron Lett. 2013, 54, 5795–5798.
  • Haan, S. L.; Smith, Z. S.; Shomsky, K. N.; Plantinga, P. W.; Atallah, T. L. Anticorrelated Electrons from High-Intensity Nonsequential Double Ionization of Atoms. Phys. Rev. A 2010, 81, 23409.
  • “Semiconductors and Devices on A Plane:Accessing Fundamental 2D Atomic Semiconductor Properties”, Invited Talk, Kenyon College, Gambier, OH, Spring 2022.
  • “Decay Associated Fourier Spectra: Visible to Shortwave Infrared Time-Resolved Emission Spectra”, Oral & Poster, American Chemical Society National Meeting and Exposition, San Diego, CA, Fall 2019.
  • “Decay Associated Fourier Spectra: Visible to SWIR Time-Resolved Emission Spectra”, Oral, Pacific Conference on Spectroscopy and Dynamics, San Diego, CA, January 2019.
  • “Decay Associated Fourier Spectroscopy: Detecting Luminescence from Visible to Shortwave”, Poster, Seaborg Symposium, Los Angeles, CA, November 2018.
  • “Defects in Narrow Bandgap 2D Semiconductors”, Poster, Gordon Research Conference: Two Dimensional Electronics Beyond Graphene, Easton, MA, June 2018.
  • “Electrostatic Screening of Charged Defects in 2D Materials”, Oral, American Physical Society Meeting, New Orleans, LA, Spring 2017.
  • “Intrinsic Doping at Liquid Electrolyte/Organic Semiconductor Interfaces”, Oral, Material Research Society Meeting and Exhibit, Boston, MA, Fall 2014.
  • “Ultrafast Charge Separation at Organic Donor-Acceptor Interfaces: Experiment and Theory”, Poster, International Conference on Science and Technology of Synthetic Metals, Atlanta, GA, 2012.
  • “Mechanistic Insights into Rhodium Catalyzed Asymmetric Allylic Substitution Reactions”, Poster, American Chemical Society National Meeting and Exposition, Boston, MA, Fall 2012.
  • “Scope of a Rhodium Catalyzed Asymmetric Allylic Substitution Reactions”, West Michigan Regional Undergraduate Science Research Conference, Grand Rapids MI, 2010.
  • “Rhodium Catalyzed Asymmetric Allylic Substitution Reactions”, West Michigan Regional Undergraduate Science Research Conference, Grand Rapids, MI, 2009.
  • “Classical Modeling of Non-Sequential Double Ionization: Recollision, Time-Delayed ionization, Drift, and Possible Reattachment”, Poster, International


Professional Memberships
  • American Chemical Society
  • Materials Research Society


Honors & Awards
  • UCLA Chemistry & Biochemistry Postdoctoral Research Award (2021)
  • ACS UCLA Research Showcase Fellowship (2019)
  • Dr. Enno and Mrs. Lucile Wolthuis Physics Scholarships (2009)
Student Collaborations
  • Corinne Boyd
  • Lauren Rutherford
  • Henry Zheng
  • Isabella Rosabal
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