About

Professor Benjamin J. Schwartz joined the faculty at UCLA in 1997 and is a Distinguished Professor specializing in materials, nanoscience, physical chemistry, and theory. His research program aims to build a molecular-level understanding of chemical reactivity in complex environments by studying condensed-phase chemical reaction dynamics through both experimental and theoretical techniques. His experimental focus is on femtosecond spectroscopies, particularly 3-pulse pump-probe experiments that allow for direct examination of transient species such as excited states of conjugated polymers and reactive solvated atoms and electrons. The theoretical work involves developing and applying algorithms to address the breakdown of the Born-Oppenheimer approximation in mixed quantum/classical simulations and creating new methods for deriving pseudopotentials used in such simulations. Professor Schwartz's research encompasses two main areas: the influence of solvent motions on chemical reaction rates and product selection in solution-phase reactions, and the electronic structure and optoelectronic behavior of semiconducting conjugated polymers. His work on solvent effects involves real-time femtosecond pump-probe spectroscopies combined with computer simulations to monitor solvent molecule motions, energy flow, and electron movements during reactions. His investigations into conjugated polymers focus on their electronic properties, energy transfer, and interactions in device contexts such as light-emitting diodes and solar cells. Throughout his career, he has contributed significantly to understanding chemical reactivity and electronic behavior in complex environments, earning numerous awards and serving in editorial and advisory roles in the scientific community.

Research topics

• Composite material
• Materials science
• Chemical engineering
• Optoelectronics
• Chemistry
• Organic chemistry
• Chemical physics

Selected publications

• Tunable Dopants with Intrinsic Counterion Separation Reveal the Effects of Electron Affinity on Dopant Intercalation and Free Carrier Production in Sequentially Doped Conjugated Polymer Films

  Advanced Functional Materials · 2020 · 103 citations

  Senior authorCorresponding
  • Materials science
  • Chemical physics
  • Chemical engineering

  Carrier mobility in doped conjugated polymers is limited by Coulomb interactions with dopant counterions. This complicates studying the effect of the dopant's oxidation potential on carrier generation because different dopants have different Coulomb interactions with polarons on the polymer backbone. Here, dodecaborane (DDB)-based dopants are used, which electrostatically shield counterions from carriers and have tunable redox potentials at constant size and shape. DDB dopants produce mobile carriers due to spatial separation of the counterion, and those with greater energetic offsets produce more carriers. Neutron reflectometry indicates that dopant infiltration into conjugated polymer films is redox-potential-driven. Remarkably, X-ray scattering shows that despite their large 2-nm size, DDBs intercalate into the crystalline polymer lamellae like small molecules, indicating that this is the preferred location for dopants of any size. These findings elucidate why doping conjugated polymers usually produces integer, rather than partial charge transfer: dopant counterions effectively intercalate into the lamellae, far from the polarons on the polymer backbone. Finally, it is shown that the IR spectrum provides a simple way to determine polaron mobility. Overall, higher oxidation potentials lead to higher doping efficiencies, with values reaching 100% for driving forces sufficient to dope poorly crystalline regions of the film.

  DOI

Recent grants

• CRC: Using Self-Organization to Control Morphology in Semiconducting Polymers

  NSF · $2.5M · 2005–2012

• Chemical Bond Breaking and the Role of Cavities in Solution Studied Using Femtosecond Spectroscopy and Mixed Quantum/Classical Molecular Dynamics Simulation

  NSF · $501k · 2009–2014

• Understanding the Effects of Liquid Structure on Chemical Bonds and Solvated Electrons Using Ultrafast Spectroscopy and Mixed Quantum/Classical Molecular Dynamics Simulation

  NSF · $470k · 2013–2016

• Understanding the Structure and Dynamics of Solvated Electrons Using Ultrafast Spectroscopy and Quantum Simulation Methods

  NSF · $543k · 2019–2024

• UNS: Taking Advantage of Metal Interpenetration to Improve the Performance of Conjugated Polymer/Fullerene-Based Photovoltaics

  NSF · $329k · 2015–2019

Frequent coauthors

• Sarah H. Tolbert

  University of California, Los Angeles

  113 shared

• John Κ. Fairbank

  53 shared

• Roderick MacFarquhar

  50 shared

• Yves Rubin

  50 shared

• Murray Mindlin

  University of Michigan–Ann Arbor

  49 shared

• Jim Watson

  49 shared

• Paul Ch'en

  Australian National University

  49 shared

• East-West Center

  University of Michigan–Ann Arbor

  49 shared

Labs

• Schwartz, Benjamin J. – UCLAPI

Education

• Postdoc, Physics

  University of California Santa Barbara

  1996

• Postdoc, Chemistry

  University of Texas at Austin

  1995

• Ph.D., Chemistry

  University of California Berkeley

  1992

• B.S. , Physics and Chemistry

  University of Michigan

  1986

Awards & honors

• Senior Editor, the Journal of Physical Chemistry
• Musher Memorial Lecture – Lectureship Grant
• Outstanding Research Award, Herbert Newby McCoy
• UCLA Distinguished Teaching Award
• Glenn T. Seaborg Award for Research Excellence

Similar researchers at University of California, Los Angeles

• Antoni Ribash-218
• Timothy Cloughesyh-173
• Owen Witteh-170
• Yu Huangh-166
• David S. Eisenbergh-159