John A. Marohn



Professor John Marohn's group is focused on imaging the structure and function of materials at the nanometer scale.  We are pushing magnetic resonance imaging to nanoscale resolution in order to study individual biomolecules and are developing and applying tools to study charge in thin-film devices -- including the drift, diffusion, trapping, and generation of charge from light.

Research Focus

  • Detecting and imaging individual electron spins
  • Quantum measurement
  • Lead halide perovskites
  • Organic photovoltaic materials
  • Unconventional semiconductors


Search PubMed for articles by “JA Marohn”.
For a current list of publications go here.
For current publications also see Orcid and Google Scholar

Representative Publications

Nanoscale magnetic resonance imaging
  • C. E. Isaac, C. M. Gleave, P. T. Nasr, H. L. Nguyen, E. A. Curley, J. L. Yoder, E. W. Moore, L. Chen, and J. A. Marohn, Dynamic nuclear polarization in a magnetic resonance force microscope experiment, Phys. Chem. Chem. Phys., 2016, 18, 8806 – 8819, URL, PMC5609491.
  • J. G. Longenecker, H. J. Mamin, A. W. Senko, L. Chen, C. T. Rettner, D. Rugar, and J. A. Marohn, High-gradient nanomagnets on cantilevers for sensitive detection of nuclear magnetic resonance, ACS Nano, 2012, 6, 9637 – 9645, URL
  • E. W. Moore, S.-G. Lee, S. A. Hickman, S. J. Wright, L. E. Harrell, P. P. Borbat, J. H. Freed, and J. A. Marohn, Scanned-probe detection of electron spin resonance from a nitroxide spin probe, Proc. Natl. Acad. Sci. U.S.A., 2009, 106, 22251 – 22256, URL
  • S. R. Garner, S. Kuehn, J. M. Dawlaty, N. E. Jenkins, and J. A. Marohn, Force-gradient detected nuclear magnetic resonance, Appl. Phys. Lett., 2004, 84, 5091 – 5093, URL
Nanoscale fluctuations
  • S. Lekkala, J. A. Marohn, and R. F. Loring, Electric force microscopy of semiconductors: Theory of cantilever frequency fluctuations and noncontact friction, J. Chem. Phys., 2013, 139, 184702, URL
  • N. Hoepker, S. Lekkala, R. F. Loring, and J. A. Marohn, Dielectric fluctuations over polymer films detected using an atomic force microscope, J. Phys. Chem. B, 2011, 115, 14493 – 14500, URL
  • S. M. Yazdanian, N. Hoepker, S. Kuehn, R. F. Loring, and J. A. Marohn, Quantifying electric field gradient fluctuations over polymers using ultrasensitive cantilevers, Nano Lett., 2009, 9, 2273 – 2279, URL
  • S. Kuehn, J. A. Marohn, and R. F. Loring, Noncontact dielectric friction, J. Phys. Chem. B, 2006, 110, 14525 – 145258, URL
Charge and ion motion in unconventional semiconductors
  • R. P. Dwyer, S. R. Nathan, and J. A. Marohn, Microsecond photocapacitance transients observed using a charged microcantilever as a gated mechanical integrator, Sci. Adv., 2017, 3, e1602951, URL
  • A. M. Tirmzi, R. P. Dwyer, T. Hanrath, and J. A. Marohn, Coupled slow and fast charge dynamics in cesium lead bromide perovskite, ACS Energy Lett., 2017, 2, 488 – 496, URL
  • R. P. Dwyer, L. E. Harrell, and J. A. Marohn, Lagrangian and impedance spectroscopy treatments of electric force microscopy, Phys. Rev. Appl., 2019, 11, 064020, URL
  • J. L. Luria, K. A. Schwarz, M. J. Jaquith, R. G. Hennig, and J. A. Marohn, Spectroscopic characterization of charged defects in polycrystalline pentacene by time- and wavelength-resolved electric force microscopy, Adv. Mater., 2011, 23, 624 – 628, URL
  • T. N. Ng, W. R. Silveira, and J. A. Marohn, Dependence of charge injection on temperature, electric field, and energetic disorder in an organic semiconductor, Phys. Rev. Lett., 2007, 98, 066101, URL
  • J. D. Slinker, J. A. DeFranco, M. J. Jaquith, W. R. Silveira, Y.-W. Zhong, J. M. Moran-Mirabal, H. G. Craighead, H. D. Abruña, J. A. Marohn, and G. G. Malliaras, Direct measurement of the electric-field distribution in a light-emitting electrochemical cell, Nat. Mater., 2007, 6, 894 – 899, URL
  • E. M. Muller and J. A. Marohn, Microscopic evidence for spatially inhomogeneous charge trapping in pentacene, Adv. Mater., 2005, 17, 1410, URL

In the news