Honors & Awards


  • NSF Graduate Research Fellow, National Science Foundation (2020-2023)

Education & Certifications


  • B.S., University of California, Berkeley, Chemical Engineering (2020)

Stanford Advisors


All Publications


  • Probing the Effects of Acid Electrolyte Anions on Electrocatalyst Activity and Selectivity for the Oxygen Reduction Reaction CHEMELECTROCHEM Zamora Zeledon, J. A., Kamat, G., Gunasooriya, G., Norskov, J. K., Stevens, M., Jaramillo, T. F. 2021; 8 (13): 2467-2478
  • Precise Colloidal Plasmonic Photocatalysts Constructed by Multistep Photodepositions NANO LETTERS Ha, H., Yan, C., Katsoukis, G., Kamat, G. A., Moreno-Hernandez, I. A., Frei, H., Alivisatos, A. 2020; 20 (12): 8661–67

    Abstract

    Natural photosynthesis relies on a sophisticated charge transfer pathway among multiple components with precise spatial, energetic, and temporal organizations in the aqueous environment. It continues to inspire and challenge the design and fabrication of artificial multicomponent colloidal nanostructures for solar-to-fuel conversion. Herein, we introduce a plasmonic photocatalyst synthesized with colloidal methods with five integrated components including cocatalysts installed in orthogonal locations. The precise deposition of individual inorganic components on an Au/TiO2 nanodumbell nanostructure is enabled by photoreduction and photo-oxidation, which selectively occurs at the TiO2 tip sites and Au lateral sites, respectively. Under visible-light irradiation, the photocatalyst exhibited activity of oxygen evolution from water without scavengers. We demonstrate that each component is essential for improving the photocatalytic performance. In addition, mechanistic studies suggest that the photocatalytic reaction requires combining the hot charge carriers derived from exciting both the d-sp interband transition and the localized surface plasmon resonance of Au.

    View details for DOI 10.1021/acs.nanolett.0c03431

    View details for Web of Science ID 000599507100036

    View details for PubMedID 33226246

  • Self-Limiting Shell Formation in Cu@Ag Core-Shell Nanocrystals during Galvanic Replacement JOURNAL OF PHYSICAL CHEMISTRY LETTERS Kamat, G. A., Yan, C., Osowiecki, W. T., Moreno-Hernandez, I. A., Ledendecker, M., Alivisatos, A. 2020; 11 (13): 5318–23

    Abstract

    The understanding of synthetic pathways of bimetallic nanocrystals remains limited due to the complex energy landscapes and dynamics involved. In this work, we investigate the formation of self-limiting Cu@Ag core-shell nanoparticles starting from Cu nanocrystals followed by galvanic replacement with Ag ions. Bulk quantification with atomic emission spectroscopy and spatially resolved elemental mapping with electron microscopy reveal distinct nucleation regimes that produce nanoparticles with a tunable Ag shell thickness, but only up to a certain limiting thickness. We develop a quantitative transport model that explains this observed self-limiting structure as arising from the balance between entropy-driven interdiffusion and a positive mixing enthalpy. The proposed model depends only on the intrinsic physical properties of the system such as diffusivity and mixing energy and directly yields a high level of agreement with the elemental mapping profiles without requiring additional fit parameters.

    View details for DOI 10.1021/acs.jpclett.0c01551

    View details for Web of Science ID 000547468400057

    View details for PubMedID 32530633

  • Factors and Dynamics of Cu Nanocrystal Reconstruction under CO2 Reduction ACS APPLIED ENERGY MATERIALS Osowiecki, W. T., Nussbaum, J. J., Kamat, G. A., Katsoukis, G., Ledendecker, M., Frei, H., Bell, A. T., Alivisatos, A. 2019; 2 (11): 7744–49
  • Low-dimensional perovskite nanoplatelet synthesis using in situ photophysical monitoring to establish controlled growth NANOSCALE Do, M., Kim, I., Kolaczkowski, M. A., Kang, J., Kamat, G. A., Yuan, Z., Barchi, N. S., Wang, L., Liu, Y., Jurow, M. J., Sutter-Fella, C. M. 2019; 11 (37): 17262–69

    Abstract

    Perovskite nanoparticles have attracted the attention of research groups around the world for their impressive photophysical properties, facile synthesis and versatile surface chemistry. Here, we report a synthetic route that takes advantage of a suite of soluble precursors to generate CsPbBr3 perovskite nanoplatelets with fine control over size, thickness and optical properties. We demonstrate near unit cell precision, creating well characterized materials with sharp, narrow emission lines at 430, 460 and 490 nm corresponding to nanoplatelets that are 2, 4, and 6 unit cells thick, respectively. Nanoplatelets were characterized with optical spectroscopy, atomic force microscopy, scanning electron microscopy and transmission electron microscopy to explicitly correlate growth conditions, thickness and resulting photophysical properties. Detailed in situ photoluminescence spectroscopic studies were carried out to understand and optimize particle growth by correlating light emission with nanoplatelet growth across a range of synthetic conditions. It was found that nanoplatelet thickness and emission wavelength increase as the ratio of oleic acid to oleyl amine or the reaction temperature is increased. Using this information, we control the lateral size, width and corresponding emission wavelength of the desired nanoplatelets by modulating the temperature and ratios of the ligand.

    View details for DOI 10.1039/c9nr04010b

    View details for Web of Science ID 000487944000040

    View details for PubMedID 31246216