Neal R. Armstrong

About

Neal R. Armstrong is a Regents' Professor of Chemistry and Biochemistry at The University of Arizona, affiliated with the Department of Chemistry and Biochemistry. He also holds the position of Regents' Professor of Optical Sciences and serves as the Director of the Energy Frontier Research Center for Interface Science: Solar Electric Materials. His research interests include interface characterization and modification, new molecular materials for energy conversion, light emission, and sensing. He specializes in surface photoemission spectroscopies such as UPS and XPS, scanning probe microscopies, electrochemistry, and related fields. Dr. Armstrong earned his Ph.D. from the University of New Mexico in 1974 and his B.S. from the same institution in 1970.

Research topics

• Materials science
• Chemistry
• Chemical engineering
• Optoelectronics
• Nanotechnology
• Inorganic chemistry
• Physical chemistry
• Organic chemistry
• Crystallography
• Metallurgy

Selected publications

• Overcoming Redox Reactions at Perovskite-Nickel Oxide Interfaces to Boost Voltages in Perovskite Solar Cells

  Joule · 2020 · 580 citations

  DOI

• Reducing Surface Recombination Velocity of Methylammonium-Free Mixed-Cation Mixed-Halide Perovskites via Surface Passivation

  Chemistry of Materials · 2021 · 62 citations

  We control surface recombination in the mixed-cation, mixed-halide perovskite, FA0.83Cs0.17Pb(I0.85Br0.15)3, by passivating nonradiative defects with the polymerizable Lewis base (3-aminopropyl)trimethoxysilane (APTMS). We demonstrate average minority carrier lifetimes >4 μs, nearly single exponential monomolecular photoluminescence decays, and high external photoluminescence quantum efficiencies (>20%, corresponding to ∼97% of the maximum theoretical quasi-Fermi-level splitting) at low excitati…

  PublisherOA PDFDOI

• Defect quantification in metal halide perovskites: the solid-state electrochemical alternative

  Energy & Environmental Science · 2021-01-01 · 17 citations

  article

  A solid-state, operando approach for defect quantification with respect to an internal energy reference using an optically and X-ray transparent electrolyte that can be easily removed.

  PublisherDOI

• Influence of the Processing Environment on the Surface Composition and Electronic Structure of Size-Quantized CdSe Quantum Dots

  The Journal of Physical Chemistry C · 2020 · 16 citations

  Senior authorCorresponding

  We show here how differences in surface composition for monolayer (ML)-tethered pyridine (Py)-treated CdSe quantum dots (QDs) affect band edge energetics, as a function of QD diameter. We compare UV–vis spectroscopy of QD solutions and X-ray (XPS) and ultraviolet (UPS) photoelectron spectroscopy of QDs tethered to 1,6-hexanedithiol-modified Au surfaces. Differences in QD surface composition are brought about by differences in solvent composition during displacement of the native, X-type octadecy…

  DOI

• Extremely Long-Lived Charge Donor States Formed by Visible Irradiation of Quantum Dots

  ACS Nano · 2024-08-20 · 15 citations

  article

  Using cyclic voltammetry under illumination, we recently demonstrated that CdS quantum dots (QDs) form charge donor states that live for at least several minutes after illumination ends, ∼12 orders of magnitude longer than expected for free carriers. This time scale suggests that the conventionally accepted mechanism of charge transfer, wherein charges directly transfer to an acceptor following exciton dissociation, cannot be complete. Because of these long time scales, this unconventional pathw…

  PublisherDOI

Recent grants

• Ultrathin Film Molecular Electronic Materials: Self-Organizing Discotic Mesophases and Organic Heterojunctions

  NSF · $860k · 2005–2009

• Characterization and Control of Structure, Energetics and Electrical Properties at Interfaces between Perovskite Active Layers and Charge-Collection Electrodes

  NSF · $404k · 2015–2018

Frequent coauthors

• Seth R. Marder

  71 shared

• S. Scott Saavedra

  University of Arizona

  69 shared

• Bernard Kippelen

  Georgia Institute of Technology

  66 shared

• Erin L. Ratcliff

  52 shared

• Kenneth W. Nebesny

  University of Arizona

  49 shared

• Stephen Barlow

  University of Colorado Boulder

  41 shared

• Ghassan E. Jabbour

  University of Ottawa

  41 shared

• Jeffrey Pyun

  University of Arizona

  40 shared

Labs

• Quantum Optomechanics LabPI

Similar researchers at University of Arizona

• Jennifer K. Bartonh-41
• Stuart F. Biggarh-36
• Brian P. Andersonh-32