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Metal halide perovskites are known to suffer from instability due to their high sensitivity to external stimuli. Although encapsulation can considerably improve their stability, the impact of encapsulation on the intrinsic photophysical properties of perovskites remains unclear. Here, we investigate the effect of hexagonal boron nitride (hBN) encapsulation on the photoluminescence (PL) dynamics of MAPbI perovskite crystals at the individual crystal level. The results demonstrate that hBN encapsulation leads to PL decline, PL lifetime shortening, and spectral broadening in MAPbI crystals, which can be ascribed to the stress exerted by hBN encapsulation on MAPbI crystals that promotes defect formation and subsequent nonradiative recombination losses. Furthermore, although hBN encapsulation can delay degradation, the effect of hBN-induced stress and the poor sealing due to single-sided encapsulation would further broaden the spectra over time. This work provides new insights into the photophysical effects of encapsulation on perovskites and has significance for the selection of perovskite encapsulation strategies.
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http://dx.doi.org/10.1021/acs.jpclett.4c03715 | DOI Listing |
Nano Lett
September 2025
Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States.
Here, we present an all-electrical readout mechanism for quasi-0D quantum states (0D-QS), such as point defects, adatoms, and molecules, that is modular and general, providing an approach that is amenable to scaling and integration with other solid-state quantum technologies. Our approach relies on the creation of high-quality tunnel junctions via the mechanical exfoliation and stacking of multilayer graphene (MLG) and hexagonal boron nitride (hBN) to encapsulate the target system in an MLG/hBN/0D-QS/hBN/MLG heterostructure. This structure allows for all-electronic spectroscopy and readout of candidate systems through a combination of coulomb and spin-blockade.
View Article and Find Full Text PDFNat Commun
August 2025
Institute of Experimental Physics I and Center for Materials Research (LaMa), Justus-Liebig-University Giessen, Heinrich-Buff-Ring 16, D-35392, Giessen, Germany.
Rabi splitting is a defining signature of strong light-matter interaction, emerging when a two-level system is resonantly driven by an optical field, resulting in a spectral doublet separated by the Rabi energy. In solid-state systems, Rabi splitting occurs at exciton resonances, where it is shaped by many-body interactions intrinsic to the material. Here, we investigate the Rabi splitting dynamics in two paradigmatic two-dimensional semiconductors: a hBN-encapsulated MoSe monolayer and a (Ga,In)As multiple quantum well structure.
View Article and Find Full Text PDFNano Lett
August 2025
Walter Schottky Institut and TUM School of Natural Sciences, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.
We investigate the confinement of neutral excitons in a one-dimensional (1D) potential engineered by proximizing hexagonal boron nitride (hBN)-encapsulated monolayer MoSe to ferroelectric domain walls (DWs) in periodically poled LiNbO. Our device exploits the nanometer scale in-plane electric field gradient at the DW to induce dipolar exciton confinement via the DC Stark effect. Spatially resolved photoluminescence spectroscopy reveals the emergence of narrow emission lines redshifted from the MoSe neutral exciton by up to ∼100 meV, depending on the sample structure.
View Article and Find Full Text PDFAdv Sci (Weinh)
August 2025
Department of Materials Science and Engineering, Seoul National University, Seoul, 18826, South Korea.
Transition metal dichalcogenides (TMDs) are promising materials for next-generation electronics due to their atomically thin body and exceptional optoelectronic properties. Their ultrathin and stiff nature make them highly sensitive to strain, enabling modulation of lattice and band structures and enhancing carrier mobility via tensile strain. While uniform strain degrades optical properties of MoS due to the indirect bandgap, localized strain enhances them through the funnel effect, highlighting the importance of localized strain engineering.
View Article and Find Full Text PDFNano Lett
August 2025
Department of Physics, University of Arizona, Tucson, Arizona 85721, United States.
Optical measurements of 2D semiconductors have primarily relied on far-field spectroscopy techniques, which are diffraction limited to several hundred nanometers. Precisely imaging nanoscale spatial disorder requires an order of magnitude increase in resolution capabilities. Here, we present a spatially resolved study of the exciton spectra of monolayer MoSe in the visible range using cryogenic scattering-type scanning near-field optical microscopy (s-SNOM) operating down to 11 K.
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