Neal R Armstrong

Regents Professor Emeritus

Degrees and Appointments

Degrees and Appointments

  • B.S. 1970, Chemistry, University of New Mexico

  • Ph.D. 1974, Analytical Chemistry, University of New Mexico

  • OSU Postdoctoral Fellow 1974-75, Ohio State University

Fields of Study: Analytical Chemistry

Awards and Honors

  • Regents Professor in Chemistry/Biochemistry/Optical Sciences, 2013
  • University of Arizona At The Leading Edge Award - Innovation Day, 2011
  • Elizabeth and Keith Hege Galileo Circle Fellow - College of Science, University of Arizona, 2011
  • Alexander von Humboldt Sr. Research Prize - Inst Appl Photophys,Tech Univ Dresden/Max Planck Inst. f, 2002
  • National Science Foundation - Special Award for Creativity, 2000

Research Specialties: Energy Science, Materials and Polymer Chemistry, Surface and Solid State

Research

Our group is focused on developing the new measurement science required to understand and control the chemical, physical and electrical properties of interfaces between electrical contacts and new electro-optical (active layer) materials, at nanometer length scales.  These materials encompass both organic active layers in organic solar cells (OPVs), hybrid perovskite active layers for new thin film solar cell technologies, and surface tethered semiconductor nanocrystals.  Such studies underpin the development of emerging energy conversion technologies (solar cells, photoactive nanocrystalline materials for light-to-fuel formation), and new active layers for light emisison, 

While reasonably efficient energy conversion and light emission platforms are becoming available, they are typyically expensive and not scalable.  The challenges in creating massively scalable energy conversion technologies, that are inexpensive and easily integrated into other technology platforms, often lies in understanding and controlling composition, structure and energetics of the interfaces between electrical contacts and active layers. 

diagram illustrating the Imact od Titanium Dioxide Surface Defects on the Interfacial Composition and Energetics of Evaprated Perovskite Active Layer

 

 

Photo from The Journal of Physical Chemstiry Letters, dated June 2, 2011/Volume 2, Number 11
illustration Selective Interlayers and Contacs in Organic Photovoltaic Cells

 Adv. energy Mater. 2016, 1502195  DOI: 10/1002/aenm.201502195

Picture representing global generation units with water stress

 

 

 

 

 

 

 

 

 

 

 

 

  • Zinc Phthalocyanine-Phosphonic Acid Monolayers on ITO: Influence of Molecular Orientation, Aggregation, and Tunneling Distance on Charge Transfer Kinetics, Luis E. Oquendo, Ramanan Ehamparam, Neal R. Armstrong, S. Scott Saavedra, Dominic V. McGrath, J. Phys. Chem. C. 123, 6970-6980 (2019) DOI:10.1021/acs.jpcc.8b10301
  • “Impact of TiO2 surface defects on the interfacial composition and energetics of evaporated perovskite active layers” R. Clayton Shallcross, Selina Olthof, Klaus Meerholz, Neal R. Armstrong, ACS Applied Materials and Interfaces August 2019; DOI: 10.1021/acsami.9b09935
  • “Challenges and Opportunities at the Nexus of Energy, Water and Food,” N.R. Armstrong, R. Clayton Shallcross, Kimberly Ogden, Shane Snyder, Andrea Achilli, Erin L. Armstrong, MRS Energy and Sustainability (www.mrs.org/energy-sustainability-journal)  5, (2018) DOI:10.1557/mre.2018.2
  • “Critical interface states controlling rectification of ultrathin NiO-ZnO p-n heterojunctions,” K. Xerxes Steirer, Kai Lin Ou, Paul Lee, Neal R. Armstrong, and Erin L. Ratcliff, ACS Applied Materials and Interfaces, 9, 31111–31118 (2017) DOI: 10.1021/acsami.7b08899
  • “Axially Bound Ruthenium Phthalocyanine Monolayers on Indium Tin Oxide: Structure, Energetics and Charge Transfer Properties,” Ramanan Ehamparam, Luis E. Oquendo, Michael W. Liao, Ambjorn K. Brynnel, Kai-Lin Ou, Neal R. Armstrong, Dominic V. McGrath, and S. Scott Saavedra, ACS Applied Materials & Interfaces, 9, 29213 - 29223 (2017) DOI: 10.1021/acsami.7b07394
  • “Determining Band-edge Energies and Morphology-Dependent Stability of Formamidinium Lead Perovskite Films Using Spectroelectrochemistry and Photoelectron Spectroscopy,” R. Clayton Shallcross, Yilong Zheng, S. Scott Saavedra, N.R. Armstrong, J. Amer. Chem. Soc. 139 4866-4878 (2017) DOI: 10.1021/jacs.7b00516.
  • “Surface modification of indium-tin oxide with functionalized perylene diimides: Characterization of orientation, electron-ˇ‐transfer kinetics and electronic structure,” Yilong Zheng, Anthony J. Giordano, R. Clayton Shallcross, Sean R. Fleming, Stephen Barlow, Neal R. Armstrong, Seth R. Marder, S. Scott Saavedra, J. Phys. Chem. C. 120, 20040–20048  (2016) DOI: 10.1021/acs.jpcc.6b06812
  • “Characterization of ZnO Interlayers for Organic Solar Cells: Correlation of Electrochemical Properties with Thin Film Morphology and Device Performance,” Kai-Lin Ou, Ramanan Ehamparam, Gordon MacDonald, Tobias Stubhan, Xin Wu, R. Clayton Shallcross, Robin Richards, Christoph J. Brabec, S. Scott Saavedra, and Neal R. Armstrong, ACS Applied Materials & Interfaces, 8, 19787-19798 (2016) DOI: 10.1021/acsami.6b02792
  • “Phosphonic acids for interfacial engineering of transparent conductive oxides,” Sergio A. Paniagua, Anthony J. Giordano, O’Neil L. Smith, Stephen Barlow, Hong Li, Neal R. Armstrong, Jeanne E. Pemberton, Jean-Luc Brédas, David Ginger, and Seth R. Marder, Chemical Reviews, 116, 7117–7158, (2016) DOI: 10.1021/acs.chemrev.6b00061.
  • “Overcoming Electrode Induced Losses in Organic Solar Cells by Tailoring a Quasi-Ohmic Contact to Fullerenes via  Solution-Processed     Alkali Hydroxide Layers,”HongZhang, R. Clayton Shallcross, Ning Li, Tobias Stubhan, Yi Hou, Wei Chen, Tayebeh Ameri, Mathieu Turbiez, Neal R. Armstrong, Christoph J. Brabec, Advanced Energy Materials, 6, 1502195, (2016), DOI: 10.1002/aenm.201502195