arXiv subjects

Eveline Mayner

Publications and source records attributed to Eveline Mayner.

3 recordsLinked to original sources

arXiv2026

Energy-Transfer-Enhanced Emission and Quantum Sensing of VB- Defects in hBN-PbI2 Heterostructures

Spin defects in two-dimensional materials hold significant potential for quantum information technologies and sensing applications. The negatively charged boron vacancy (VB-) in hexagonal boron nitride (hBN) has attracted considerable attention as a quantum sensor due to its demonstrated sensitivity to temperature, magnetic fields, and pressure.1 However, its applications have thus far been limited by inherently dim photoluminescence (PL). By fabricating a van der Waals heterostructure with a sensitizing donor layer, lead iodide (PbI2), we effectively enhance the PL intensity from the VB- by 5-45x, while maintaining compatibility with other heterostructures and vdW optoelectronic platforms. The type-I band alignment at the heterojunction enables efficient exciton migration while suppressing back-electron transfer, and the strong spectral overlap between the PbI2 emission and defect absorption supports efficient fluorescence resonance energy transfer. Ab initio density functional theory (DFT) predicts a photon-ratcheting mechanism that boosts absorption and emission while maintaining magnetic resonance (ODMR) contrast through minimal hybridization. Experimentally, the heterostructure exhibits enhanced continuous-wave ODMR sensitivity and functions as a precise probe of external magnetic fields. This work establishes a proof-of-concept for amplifying weak defect signals in nanomaterials, highlighting a new strategy for engineering their optical and magnetic responses.

cond-mat.mtrl-sci↗

arXiv2024

Emission dipole orientation reveals dynamic single-molecule interactions with 2D crystals at solvent interfaces

Direct observation of individual fluorescent emitters is crucial for understanding and studying quantum materials, chemical reactions, and biological systems. However, current single-molecule tracking methods only focuses on the localizations of molecules, overlooking molecular configuration and orientation. In this work, we introduce a high-throughput polarized single-molecule localization microscopy that simultaneously resolves the locations and emission dipole orientations of single fluorescent emitters with nanometer precision. Using the interface between pristine hexagonal boron nitride (h-BN) and an organic solvent as a challenging platform, we capture over 10^5 fluorescent events and reveal distinct molecular interaction dynamics at room temperature. The measured dipole orientations align with the three-fold rotational symmetry of the h-BN lattice, and molecular dynamics in the liquid enivronment can be modulated electrochemically, suggesting a route for on-demand control of quantum emitters. We also find that lateral diffusion at the solid-liquid interface is far more dynamic than that of solid-state emitters. This simultaneous tracking of molecular conformation and photophysics advances the understanding of single-molecule interactions and enables real-time sensing through two-dimensional materials.

cond-mat.mes-hall↗

arXiv2024

Monitoring electrochemical dynamics through single-molecule imaging of hBN surface emitters in organic solvents

Electrochemical techniques conventionally lack spatial resolution and average local information over an entire electrode. While advancements in spatial resolution have been made through scanning probe methods, monitoring dynamics over large areas is still challenging, and it would be beneficial to be able to decouple the probe from the electrode itself. In this work, we leverage single molecule microscopy to spatiotemporally monitor analyte surface concentrations over a wide area using unmodified hexagonal boron nitride (hBN) in organic solvents. Through a sensing scheme based on redox-active species interactions with fluorescent emitters at the surface of hBN, we observe a linear decrease in the number of emitters under positive voltages applied to a nearby electrode. We find consistent trends in electrode reaction kinetics vs overpotentials between potentiostat-reported currents and optically-read emitter dynamics, showing Tafel slopes greater than 290 mV per decade. Finally, we draw on the capabilities of spectral single molecule localization microscopy (SMLM) to monitor the fluorescent species identity, enabling multiplexed readout. Overall, we show dynamic measurements of analyte concentration gradients at a micrometer-length scale with nanometer-scale depth and precision. Considering the many scalable options for engineering fluorescent emitters with 2D materials, our method holds promise for optically detecting a range of interacting species with unprecedented localization precision.

cond-mat.mes-hall↗