Kenneth Knappenberger
Pennsylvania State University, PA·Chemistry
When light hits a tiny piece of metal, the energy it delivers sets electrons and atoms moving, and that motion eventually becomes heat. Electronic and vibrational motion controls how energy flows in matter, so understanding it matters for technologies that turn light into heat or chemical work.
- Fields
Chemistry
Materials Science
Physics
- Topics
metal nanoclusters
atomically precise nanoclusters
monolayer-protected clusters
- Grants
- 1 known grant, through May 2027
What they work on
- Test whether the lifetimes of excited electronic states in atomically precise metal nanoclusters can control how their acoustic modes (whole-particle vibrations) are excited, using coherent multidimensional laser spectroscopy and theory.
- Determine how lattice packing structure and nanocluster shape control vibration-driven conversion of absorbed light into heat in ligand-protected metal nanoclusters.
- Investigate how substituting different metal atoms into nanoclusters changes chiroptical excitation (response to left- vs right-handed light) and the energy transfer that follows.
- Map how electronic and vibrational properties evolve from molecule-like to metal-like behavior across clusters from sub-nanometer to a few nanometers, combining precision synthesis, time-resolved spectroscopy and modeling.
More about the research
Linking a material's structure to how it converts energy is hard, however, because most materials are a mix of slightly different structures. This collaborative project, involving Penn State, Kansas State and Carnegie Mellon, gets around the problem by using atomically precise metal nanoclusters. These are particles a few nanometers or smaller in which every atom's position is known. They are protected by a single layer of attached molecules called ligands.
Why it matters
Many technologies convert light into heat. Knowing exactly how a metal particle's structure controls this conversion could guide the design of photothermal technologies, including photodynamic therapy, photocatalysis, integrated circuits, mass sensing and materials manufacturing. Control of cluster vibrations could lead to high-precision nanomechanical resonators. The resulting structure-property rules may also inform catalyst design and quantum information science.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Chenjie Zeng
University of Florida, FL·Chemistry
Control the surface structures of atomically precise II-VI semiconductor nanoclusters by tailoring the metal-ligand complexes used in cation exchange, the reaction that swaps metal ions inside an intact cluster framework.
Francis Zamborini
University of Louisville, KY·Chemistry
Electrodeposit atomically precise metal nanoclusters of controlled size on electrodes, using phosphine and phosphonium stabilizing ligands and tuning nucleation density and the stabilizer-to-metal-ion ratio.
Tianquan Lian
University of Pennsylvania, PA·Chemistry
Extend electron spin lifetimes in semiconductor nanoplatelets by increasing electron–hole separation in three-component nanoplatelet heterostructures (crystals built from layered materials), then use the best structures as donors.
The school
Pennsylvania State University: 60 labs on PI Pages, $1.3B a year on research, 743 research doctorates a year.
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