Stephen O’Brien, Ph.D.

  • Professor, The City College of New York
  • Affiliate Faculty, Nanoscience Initiative


Department of Chemistry, The City College of New York (Profile)

Research Interests

Nanomaterials and nanocomposites. Energy storage and power conversion. Capacitors and electronic devices. Nanomaterials synthesis, properties and structural characterization. Chemical deposition techniques and self-assembly. Superlattices and thin films. Transition metal oxide nanomaterials, high k dielectrics/memory materials. Multiferroics, magneto-optical materials and photonic materials. Design of nanostructures for biomedical applications.

Job History

  • 2020 – Current: Chair of Department and Professor, The City College of New York
  • 2009 – Current: Principal Investigator, CUNY Energy Institute
  • 2009 – Current: Chair, Nanotechnology and Materials, The Graduate Center, CUNY
  • 1993 – 1998: D. Phil, Oxford University, UK


R.H. Huang, N. Nayeem, Y. He, J. Morales, D. Graham, R. Klajn, M. Contel, S. O’Brien, and R.V. Ulijn. Self‐Complementary Zwitterionic Peptides Direct Nanoparticle Assembly and Enable Enzymatic Selection of Endocytic Pathways, Adv. Mater., 2021, 2104962, DOI:

Q. Zhang, E.C. Pratt, R. Tamura, A. Ogirala, H-T. Hsu, N. Farahmand, S. O’Brien, J. Grimm, Ultrasmall Downconverting Nanoparticle for Enhanced Cerenkov Imaging, Nanoletters2021, 2021, 21, 10, 4217–4224.

N. Farahmand, C.K. McGinn, Q. Zhang, Z. Gai, I. Kymissis, S. O’Brien, Magnetic and Dielectric Property Control in the Multivalent Nanoscale Perovskite Eu0.5Ba0.5TiO3Nanoscale2021, 13, 10365-10384.

R. Collison, J.B. Pérez-Sánchez, M. Du, J. Trevino, J. Yuen-Zhou, S. O’Brien, and V.M. Menon, Purcell Effect of Plasmonic Surface Lattice Resonances and Its Influence on Energy Transfer, ACS Photonics2021, 8, 8, 2211-2219.

C.K. McGinn, N. Farahmand, I. Kymissis, and S. O’Brien, Morphology of Small Diameter Barium Titanate Nanoparticle and Polyvinylidene Diflouride-Trifluoroethylene Composites, IEEE International Symposium on Applications of Ferroelectrics (ISAF)2021, pp. 1-4, doi: 10.1109/ISAF51943.2021.9477346.

F.A. Pearsall, J. Lombardi, N. Farahmand, B.V. Tassel, E.S. Leland, L. Huang, S. Liu, S. Yang, C. Le, I. Kymissis, P. Kinget, S.R. Sanders, D. Steingart, S. O’Brien, Polymer-Nanocrystal Nanocomposites: Device Concepts in Capacitors and Multiferroics, IEEE Transactions on Nanotechnology, 2020, DOI: 10.1109/TNANO.2019.2939093.

F. Pearsall, N. Farahmand, J. Lombardi, S. Dehipawala, Z. Gai, S. O’Brien, Structure–property trends in a hollandite multiferroic by Fe doping: structural, magnetic and dielectric characterization of nanocrystalline BaMn3−xFexTi4O14+δ, Mater. Chem. C, 2020,

H.R. Huang, N.B. Sobol, A. Younes, T. Mamun, J.S. Lewis, R.V. Ulijn, S.P. O’Brien, Comparison of Methods for Surface Modification of Barium Titanate Nanoparticles for Aqueous Dispersibility: Towards Biomedical Utilization of Perovskite Oxides, ACS Appl. Mater. Interfaces, 2020DOI:

J. Lombardi, L. Yang, F.A. Pearsall, N. Farahmand, Z. Gai, J.L. Billinge, S. O’Brien, Stoichiometric Control Over Ferroic Behavior in Ba(Ti1-xFex)O3 Nanocrystals, Chemistry of Materials, 2019, DOI:10.1021/acs.chemmater.8b04447.

E.S. Leland, P.R. Kinget, I. Kymissis, D. Steingart, S.R. Sanders, S. O’Brien, Nanocomposite Capacitors in Power Electronics and Multiferroics, IEEE Nanotechnology Magazine, 2018, 10.1109/MNANO.2018.2881331.