About

Harry L. Tuller is the R.P. Simmons Professor of Ceramics and Electronic Materials and a Professor of Materials Science and Engineering at MIT. He is a world-renowned expert in electroceramics, a class of ceramic materials that enable technologies such as energy conversion, environmental sensing, electronics, and communications. His research focuses on solid-state ionics, which examines the movement of ions, or charged atoms, in solids such as ceramics. His group models, processes, and optimizes energy-related devices including sensors, batteries, and fuel cells, as well as microelectromechanical systems (MEMS). Professor Tuller received a BS and an MS in electrical engineering and a doctorate in solid-state science and engineering, all from Columbia University. Prior to joining MIT, he served as a postdoctoral research associate at Technion in Israel. He has published more than 500 articles, co-edited 15 books, and holds 33 patents. He is also the editor-in-chief of the Journal of Electroceramics and series editor of Electronic Materials: Science and Technology. Additionally, he is a co-founder of Boston MicroSystems, a pioneer in silicon carbide-based MEMS technology and devices.

Research topics

• Materials science
• Computer Science
• Bioinformatics
• Optoelectronics
• Nanotechnology
• Physical chemistry
• Inorganic chemistry
• Chemical engineering
• Chemistry

Selected publications

• Electrochemical Oxygen Pump Assisted Solar Thermochemical CO2 Reduction

  Research Square · 2026-01-23

  preprintOpen access
  PublisherOA PDFDOI

• Acidity‐Mediated Metal Oxide Heterointerfaces: Roles of Substrates and Surface Modification

  Advanced Materials · 2025-10-04 · 2 citations

  articleOpen accessSenior authorCorresponding

  Abstract Although strong modulation of interfacial electron concentrations by the relative acidity of surface additives is suggested, direct observation of corresponding changes in surface conductivity, crucial for understanding the role of local space charge, is lacking. Here, a model platform comprising well‐aligned mixed ionic‐electronic conducting Pr 0.2 Ce 0.8 O 2‐δ nanowire arrays (PCO NA ) is introduced to show that acidity‐modulated heterointerfaces predict electron depletion or accumulation, resulting in tunable electrical properties. Three orders of magnitude increased PCO NA conductivity are confirmed with basic Li 2 O infiltration. Moreover, the relative acidity of the insulating substrate supporting the PCO NA strongly influences its electronic properties as well. This strategy is further validated in purely ionic‐conducting nanostructured ceria as well as PCO NA . It is suggested that observed conductivity changes stem not only from acidity‐mediated space charge potentials at heterointerfaces but also from grain boundaries, chemically‐modulated by cation in‐diffusion. These findings have broad implications for how substrate and surface treatment choices can alter the conductive properties of nanostructured functional oxides.

  PublisherDOI

• Unveiling critical role of metal oxide infiltration in controlling the surface oxygen exchange activity and polarization of SrTi_1−<i>x</i>Fe_<i>x</i>O_{3−<i>δ</i>} perovskite oxide electrodes

  Journal of Materials Chemistry A · 2025-01-01 · 5 citations

  articleOpen accessCorresponding

  Surface oxygen exchange coefficients, k chem , of SrTi 1− x / 100 Fe x /100 O 3− δ ( x = 35, 50, 80) before and after CaO-activation and Al 2 O 3 -deactivation at 575 °C.

  PublisherOA PDFDOI

• Field Driven Solid-State Defect Control of Bilayer Switching Devices: Ionic Transport Kinetics within Layers and across the Interfaces

  ACS Applied Materials & Interfaces · 2025-08-26

  articleSenior authorCorresponding

  Nanoionic devices, crucial for neuromorphic computing and ionically enabled functional actuators, are often kinetically limited. In bilayer configurations, experimentally deconvoluting ion transport within individual layers from the kinetics of transfer across solid–solid interfaces, however, remains a challenge, hindering rational device optimization. Here, we extend the dynamic current–voltage (I–V) technique to a PrxCe1–xO2/La2–xCexCuO4 (PCO/LCCO) bilayer system, enabling the isolation and quantification of distinct ion transport processes. At high sweep rates, the technique allows quantification of the intralayer transport kinetics within the PCO layer, demonstrating the strong dependence of oxygen vacancy mobility on defect concentration (varying from 2.06 × 10–12 to 7.31 × 10–12 cm2 V–1 s–1 at 50 °C, with activation energies of 0.69–0.86 eV). At lower sweep rates, we identify the kinetic signature of interlayer ion exchange. Arrhenius analysis yields a significantly higher activation energy of 1.03 ± 0.1 eV for this process that we associate with the existence of an interfacial energy barrier, rather than bulk diffusion. This work introduces a methodological framework for studying the transport kinetics of ions in functional bilayers devices, revealing pathways to optimize the speed and performance of such devices.

  PublisherDOI

• Optoionics: New opportunity for ionic conduction-based radiation detection

  MRS Communications · 2025-05-13

  articleOpen accessSenior author

  Optoionics, involving light-modulated ionic transport in ionic solids, parallels optoelectronics in semiconductors and offers novel device design opportunities across various fields. Among these opportunities, grain boundary phenomena related to radiation-induced electron/hole pair generation and charge trapping at the boundaries causing a modulation in ionic current could enable fast, sensitive, and reversible radiation detectors. The robustness of ionic solids in chemical, structural, and thermal aspects in turn makes them scalable and robust alternatives to traditional semiconductor detectors. This article explores the theoretical underpinnings, experimental breakthroughs, and design considerations needed to optimize such optoionic devices.

  PublisherOA PDFDOI

• Grain Boundary Space Charge Engineering of Solid Oxide Electrolytes: Model Thin Film Study

  Advanced Functional Materials · 2025-09-23 · 1 citations

  articleOpen accessSenior authorCorresponding

  Abstract Grain boundaries (GB) profoundly influence the electrical properties of polycrystalline ionic solids. Yet, precise control of their transport characteristics has remained elusive, thereby limiting the performance of solid‐state electrochemical devices. Here, unprecedented manipulation of space charge controlled ionic grain boundary resistance (up to 12 orders of magnitude) in metal oxide thin films are demonstrated. The orders of magnitude higher grain boundary diffusivities of substrate cation elements (i.e., Al from Al 2 O 3 and Mg from MgO) relative to the bulk are exploited to modify the grain boundary chemistry, and thereby GB core charge, in a model oxygen ion conducting polycrystalline thin film solid electrolyte, Gd‐doped CeO 2 . This approach, confirmed jointly by TEM imaging and SIMS analysis, enabled us to selectively control the chemistry of the GBs, while minimally modifying grain (bulk) chemistry or film microstructure, thereby ruling out potential effects of microstructure, strain or secondary phases. Broad tuning of GB space charge potentials is achieved by manipulating GB core charge density by over an order of magnitude, thereby providing a powerful tool for systematic studies of grain boundary phenomena across various functional materials. The implications of such control are far‐reaching in achieving new functionality, improving efficiency, and longevity of solid‐state electrochemical devices.

  PublisherOA PDFDOI

• Ionic conduction-based polycrystalline radiation detection

  2025-07-31

  article

  Solid-state radiation detection relies on scintillation and semiconductor materials that exist in single-crystal, amorphous, and polycrystalline (ceramic) forms. Single crystals typically provide superior uniformity and spectroscopic performance but present challenges in fabrication, particularly for high-melting-point materials. Ceramics offer an alternative with potential cost advantages and the capability to incorporate compositions that are unstable in melt growth. Additionally, defects may be more readily controlled in post-growth annealing treatments of small grains compared to large melt-grown single crystals. However, ceramic fabrication introduces grain boundaries, which influence charge transport and serve as electron-hole recombination centers. This work explores a high-density, high-effective-Z, oxygen-ion-conducting ceramic material, Gd(+3)-doped CeO₂ (CeO₂:Gd), for radiation detection, focusing on materials fabrication and electrical characterization. A key aspect of this study involves chemically engineering the grain boundaries, thereby modifying the material’s opto-ionic response, where excitation alters ionic conduction by reducing space charge barriers at the grain boundaries. The work investigates this mechanism in relation to its impact on charge transport and signal generation. CeO₂:Gd’s wide bandgap (&gt;3 eV) results in a lower and more stable dark signal current compared to lower-bandgap single-crystal materials, providing stable performance to higher temperatures and harsh environments. This work presents the current-voltage curves of CeO₂:Gd devices and their response to 375nm photon and 84-kVp x-ray excitation.

  PublisherDOI

• Electrical conductivity enhancement in yttrium iron garnet: Effects of Ca substitution and Fe deficiency

  Journal of Alloys and Compounds · 2025-05-18

  article
  PublisherDOI

• Acidity-Mediated Metal Oxide Heterointerfaces: Roles of Substrates and Surface Modification

  ArXiv.org · 2025-05-20

  preprintOpen accessSenior author

  Although strong modulation of interfacial electron concentrations by the relative acidity of surface additives has been suggested, direct observation of corresponding changes in surface conductivity, crucial for understanding the role of local space charge, has been lacking. Here, we introduce a model platform comprising well-aligned mixed ionic-electronic conducting $\mathrm{Pr}_{0.2}\mathrm{Ce}_{0.8}\mathrm{O}_{2-δ}$ nanowire arrays ($\mathrm{PCO}_{\mathrm{NA}}$) to show that acidity-modulated heterointerfaces predict electron depletion or accumulation, resulting in tunable electrical properties. We confirm three orders of magnitude increased $\mathrm{PCO}_{\mathrm{NA}}$ conductivity with basic $\mathrm{Li}_{2}\mathrm{O}$ infiltration. Moreover, the relative acidity of the insulating substrate supporting the $\mathrm{PCO}_{\mathrm{NA}}$ strongly influences its electronic properties as well. This strategy is further validated in purely ionic-conducting nanostructured ceria as well as $\mathrm{PCO}_{\mathrm{NA}}$. We suggest that observed conductivity changes stem not only from acidity-mediated space charge potentials at heterointerfaces but also from grain boundaries, chemically-modulated by cation in-diffusion. These findings have broad implications for how substrate and surface treatment choices can alter the conductive properties of nanostructured functional oxides.

  PublisherOA PDFDOI

• Grain Boundary Space Charge Engineering of Solid Oxide Electrolytes: Model Thin Film Study

  ArXiv.org · 2025-04-14

  preprintOpen accessSenior author

  Grain boundaries (GB) profoundly influence the electrical properties of polycrystalline ionic solids. Yet, precise control of their transport characteristics has remained elusive, thereby limiting the performance of solid-state electrochemical devices. Here, we demonstrate unprecedented manipulation of space charge controlled ionic grain boundary resistance (up to 12 orders of magnitude) in metal oxide thin films. We exploit the orders of magnitude higher grain boundary diffusivities of substrate cation elements (i.e. Al from $Al_2O_3$ and Mg from MgO) relative to the bulk to modify the grain boundary chemistry, and thereby GB core charge, in a model oxygen ion conducting polycrystalline thin film solid electrolyte, Gd-doped $CeO_2$. This approach, confirmed jointly by TEM imaging and by extracting the respective GB and bulk diffusivities from measured SIMS profiles, enabled us to selectively control the chemistry of the GBs, while minimally modifying grain (bulk) chemistry or film microstructure, thereby ruling out potential effects of microstructure, strain or secondary phases. Broad tuning of GB space charge potentials is achieved by manipulating GB core charge density by over an order of magnitude, thereby providing a powerful tool for systematic studies of grain boundary phenomena across various functional materials. The implications of such control are far-reaching in achieving new functionality, improving efficiency and longevity of solid-state electrochemical devices.

  PublisherOA PDFDOI

Recent grants

• BaSnO3 as a Transparent Mixed Ionic-Electronic Conducting Material - Utilizing Novel In Situ Methods to Advance Understanding of Structure-Processing-Property Relations

  NSF · $564k · 2015–2020

• Sensors: High Selectivity Gas Sensing by Photostimulation of Semiconducting Metal Oxides

  NSF · $256k · 2004–2008

• Materials World Network: In-Situ Investigation of Model Multi-Component Catalyst Systems

  NSF · $390k · 2009–2013

• NSF-Europe: Nano-Structured Ionic Materials: Impact on Properties and Performance

  NSF · $720k · 2004–2009

Frequent coauthors

• Sean R. Bishop

  Sandia National Laboratories California

  177 shared

• Nicola H. Perry

  University of Illinois Urbana-Champaign

  83 shared

• Bilge Yildiz

  Massachusetts Institute of Technology

  74 shared

• Jae Jin Kim

  Argonne National Laboratory

  56 shared

• Di Chen

  46 shared

• Dario Marrocchelli

  Massachusetts Institute of Technology

  37 shared

• Il‐Doo Kim

  34 shared

• WooChul Jung

  32 shared

Awards & honors

• 2022 Fellow, Materials Research Society
• 2019 Thomas Egleston Medal, Columbia University
• 2004 Docteur Honoris Causa, University of Provence, France
• 1997-2002 Humboldt Research Award, Alexander von Humboldt Fo…
• 1984 Fellow, American Ceramics Society