Quantum Energy Transfer in Advanced Physics

Scientists have demonstrated a striking new way that energy can move through a quantum system with almost no loss. In a recent experiment, physicists created a one-dimensional quantum channel using ultracold atoms confined to an extremely narrow path. Within this system, energy and momentum flowed freely without degrading into heat, a behavior rarely seen in everyday materials. The result mirrors a fundamental idea in quantum physics: under the right conditions, certain systems can transport energy almost perfectly. What makes this discovery important is not that it introduces a new wire or device, but that it provides a clear experimental window into how quantum systems move energy when the usual sources of friction disappear. The researchers measured what are known as Drude weights, quantities that reveal whether transport is dissipative or nearly lossless. Their measurements confirmed that this quantum gas supports long-lived, coherent transport. While this experiment does not yet transmit digital data or power electronics, it offers essential insight into the physics that could one day inform ultra-efficient quantum technologies. Understanding near-lossless transport is a key step toward future advances in quantum computing, precision sensors, and low-energy information systems. At its core, this study reminds us that nature already knows how to move energy with extraordinary efficiency — and modern physics is only beginning to learn how to listen. Study published in Science “Characterizing transport in a quantum gas by measuring Drude weights” https://lnkd.in/gq-iwEQs

Our latest work just published in JACS Steering Energy Transfer Pathways through Mn-Doping in Perovskite Nanocrystals | Journal of the American Chemical Society https://lnkd.in/gyhz5f9N Modulation of singlet and triplet energy transfer from excited semiconductor nanocrystals to attached dye molecules remains an important criterion for the design of light-harvesting assemblies. Whereas one can consider the selection of donor and acceptor with favorable energetics, spectral overlap, and kinetics of energy transfer as a means to direct the singlet and triplet energy transfer pathways, it is not obvious how to control the singlet and triplet characteristics of the donor semiconductor nanocrystal itself. By doping CsPb(Cl0.7Br0.3)3 nanocrystals with Mn2+, we have now succeeded in increasing the triplet characteristics of semiconductor nanocrystals. The singlet and triplet energy transfer between excited Mn-CsPb(Cl0.7Br0.3)3 nanocrystals and a cyanine dye (4,5-benzoindotricarbocyanine) show the participation of band gap states in singlet energy transfer and Mn2+-activated states in triplet energy transfer. By tracking donor and acceptor emission as well as transient absorption spectral features, we were able to distinguish the two independent energy transfer pathways. Whereas singlet energy transfer from the exciton emission band remains unchanged (2%), increasing the concentration of Mn2+ in perovskite nanocrystals results in an increase of triplet energy transfer yield up to 17.5%. The ability to enhance the triplet transfer yield in CsPb(Cl0.7Br0.3)3 nanocrystals through Mn-doping opens up new opportunities to develop optoelectronic and display devices.

CFN scientists Abdullah Al-Mahboob, SUJI PARK, and Houk Jang, working with Professor Maciej Molas and colleagues from the University of Warsaw, discovered an efficient & unusual energy transfer process — from a lower bandgap semiconductor material to a higher one, in stacked heterostructures of the transition metal dichalcogenide 2D materials tungsten diselenide (WSe2) and molybdenum disulfide (MoS2).   How can this be, you say?  Energy flows downhill, not uphill.  Right?   Right!   Although the team's discovery is surprising and at-first seems counter-intuitive, in this case the effect results from a fortuitious resonant overlap between high-lying excitonic states in the two materials.     Accessing and efficiently making use of this resonance relies on precisely controlling the separation distance between the two 2D materials, which the team did by interleaving them with a nanoscale layer of insulating hexagonal boron nitride. These heterostructures were made using the CFN Quantum Material Press (www.bnl.gov/qpress) — which is a unique in the world instrument for stacking 2D materials.    The energy transfer process designed into the stacked heterostructure enhances the MoS2 photoluminescence, compared to that from the MoS2 monolayer by itself.  Moreover, this work illuminates pathways to increasing the quantum efficiency of Transition Metal Dichalcogenide 2D materials for optoelectronic and photovoltaic applications.  Exciting!   Check out the details of this exciting work in Nano Letters:   https://lnkd.in/etSfK-rj   The QPress, and many other state-of-the-art instruments, are available for use by scientists from around the world, including YOU.   Take a moment and visit the CFN webpage to learn more about how we're ready to help you achieve your highest nanoscience research aspirations: http://www.bnl.gov/cfn #CFNatBrookhaven