Andriy Baumketner
Fellow 2024/2025
Physics/Astronomy
Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, Kyiv
Volkswagen Stiftung
andrij@icmp.lviv.ua
Bio
Andrij Baumketner was born on October 3, 1973, in Boryslav, Lviv Oblast, Ukraine, into a family of public servants.
In 1990, he entered Ivan Franko Lviv State University and graduated in 1995 with a degree in physics. He then pursued graduate studies at the Institute for Condensed Matter Physics (ICMP), NAS of Ukraine, earning a PhD in theoretical physics in 1999.
With a strong passion for mathematics and science from an early age, he attended an advanced placement class focused on physics and mathematics. During his university years, he began research projects in his third year of study and graduated with honors.
Between 2000 and 2006, he completed two postdoctoral appointments—first at Kanazawa University in Japan and then at the University of California, Santa Barbara (UCSB). His time at UCSB, a leading research institution, was transformative, providing opportunities to collaborate with Nobel laureates and refine his expertise.
In 2006, he secured a tenure-track assistant professor position in physics at the University of North Carolina Charlotte. While primarily focused on teaching, he also obtained several research grants. However, in 2013, his tenure application was denied, prompting a shift in his career path.
That same year, he returned to Lviv, Ukraine, where he currently holds a permanent research position at ICMP. His work focuses on three key priorities: building a research group, securing external funding, and mentoring students, with steady progress in all areas.
NANOcrystals with Variable Shape: A Theoretical VieWpoint
Lead-halide perovskite nanocrystals (LHP NCs) are a promising class of colloidal quantum dots (QDs) with applications in classical (displays, lighting) and quantum (single-photon and entangled-photon sources) light generation. Their optical properties are strongly influenced by shape, which determines exciton fine structure, anisotropic quantum confinement, and polarized emission.
CsPbBr₃ NCs typically adopt a cuboid shape, reflecting their orthorhombic crystal symmetry, but variations exist, ranging from nearly cubic to nanoplatelets or nanorods. Transmission electron microscopy (TEM) images from Prof. Maksym Kovalenko’s lab at ETH Zurich reveal aspect ratios between 1 and 4, depending on synthesis conditions.
The project hypothesizes that NC shape is thermodynamically controlled, meaning aspect ratio depends only on temperature, not growth rate. Preliminary evidence supports this, suggesting that lower temperatures favor shorter nanoparticles, while higher temperatures yield longer nanorods, following principles similar to Wulff construction for macroscopic crystals.
The goal is to test this hypothesis theoretically and determine its microscopic origins. Analytical models and computer simulations will explore mechanisms behind shape anisotropy, focusing on:
- (a) intrinsic crystal anisotropy via surface tension measurements,
- (b) ligand binding free energy,
- (c) finite surface coverage,
- (d) finite-size effects unrelated to crystal facets.
Simulation insights will guide further experiments, enhancing understanding of CsPbBr₃ NC shape formation and self-assembly at the nanoscale.