Bio

Following undergraduate studies and postgraduate research in the United Kingdom, using synchrotron radiation to study the crystalline structures of semiconductors for solar energy applications, Kieran's work at Stanford now focusses on using related diffraction techniques on an ultra-fast timescale to study ion hopping in solid electrolytes for all solid-state batteries.

Professional Education

  • PhD, University of Cambridge, Physics (2024)
  • MChem, University of Oxford, Chemistry (2019)

Stanford Advisors

Contact

  • Academic
    kwporr@stanford.edu
    University - Scholar Department: Materials Science and Engineering Position: Postdoctoral Scholar

Additional Info

Links

Current Research and Scholarly Interests

Kieran’s current research focuses on improving solid-state electrolytes for batteries and fuel cells. Key challenges for these technologies include replacing the harmful and flammable liquid electrolytes currently used as industry standards and achieving fast charging to improve commercial competitiveness, especially in the transportation sector. Substituting current ion transport media with a highly conductive solid-state electrolyte has the potential to address these challenges, drastically improving energy storage and energy conversion devices. However, the precise mechanism of ion hopping in solids is poorly understood, having been studied primarily from theoretical and computational standpoints. Kieran uses a suite of atomic-scale sensitive real-time structural probes making heavy use SLAC’s X-ray diffraction capabilities to gain a detailed, mechanistic understanding of how ions are transported through solid electrolytes.

Lab Affiliations

All Publications

  • Strain Heterogeneity and Extended Defects in Halide Perovskite Devices ACS ENERGY LETTERS Orr, K. P., Diao, J., Dey, K., Hameed, M., Dubajic, M., Gilbert, H. L., Selby, T. A., Zelewski, S. J., Han, Y., Fitzsimmons, M. R., Roose, B., Li, P., Fan, J., Jiang, H., Briscoe, J., Robinson, I. K., Stranks, S. D. 2024; 9 (6): 3001-3011

    Abstract

    Strain is an important property in halide perovskite semiconductors used for optoelectronic applications because of its ability to influence device efficiency and stability. However, descriptions of strain in these materials are generally limited to bulk averages of bare films, which miss important property-determining heterogeneities that occur on the nanoscale and at interfaces in multilayer device stacks. Here, we present three-dimensional nanoscale strain mapping using Bragg coherent diffraction imaging of individual grains in Cs0.1FA0.9Pb(I0.95Br0.05)3 and Cs0.15FA0.85SnI3 (FA = formamidinium) halide perovskite absorbers buried in full solar cell devices. We discover large local strains and striking intragrain and grain-to-grain strain heterogeneity, identifying distinct islands of tensile and compressive strain inside grains. Additionally, we directly image dislocations with surprising regularity in Cs0.15FA0.85SnI3 grains and find evidence for dislocation-induced antiphase boundary formation. Our results shine a rare light on the nanoscale strains in these materials in their technologically relevant device setting.

    View details for DOI 10.1021/acsenergylett.4c00921

    View details for Web of Science ID 001235278400001

    View details for PubMedID 38911532

    View details for PubMedCentralID PMC11190982

https://orcid.org/0000-0001-9996-1458