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1. Enhancing Quantum Emission from Spin Defects in Hexagonal Boron Nitride with a Plasmonic Nanocavity

   https://doi.org/10.1364/CLEO_FS.2023.FTh3A.1  

   Xu, Xiaohui; Solanki, Abhishek. B.; Sychev, Demid; Gao, Xingyu; Peana, Samuel; Baburin, Alexander S.; Pagadala, Karthik; Martin, Zachariah O.; Chowdhury, Sarah N.; Chen, Yong P.; et al (January 2023, Enhancing Quantum Emission from Spin Defects in Hexagonal Boron Nitride with a Plasmonic Nanocavity)

   We report a 250-fold photoluminescence enhancement of V_B^-spin-defects in hBN by coupling them to nanopatch antennas (NPA). Considering the relative size of the NPAs and laser-spot, an actual enhancement of 1695 times is determined. 

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2. Giant Plasmonic Enhancement of Chiroptical Properties by Anisotropic Gold Nanocrystals Grown In Situ in a Chiral Polymer

   https://doi.org/10.1002/adom.202400914  

   Abraham, Shema R; Joseph, Jojo P; Rajapakse, B Medini; Dutta, Avisek; Das, Rahul Kumar; Kuzmin, Andrey; Baev, Alexander; Velarde, Luis; Prasad, Paras N; Swihart, Mark T (July 2024, Advanced Optical Materials)

   Abstract Polymer‐based chiral materials with exceptional optical activity can dramatically impact integrated chiral photonics due to the tunability of their optical responses coupled with ease of fabrication. Realizing these applications requires increasing the absorbance dissymmetry factor. Here, in situ, the synthesis of gold nanostars is introduced in a chiral polymer medium to produce chiral polymer‐anisotropic plasmonic nanocrystal nanocomposites. The optimized nanocomposite shows a tenfold enhancement of dissymmetry factor,g_abs(up to 0.64) and a corresponding 46‐fold augmented circular dichroism (CD) value upon annealing, relative to the annealed pure chiral polymer film. Moreover, the enhancement relative to the non‐annealed polymer‐gold nanostar nanocomposite is strikingly higher: a 35‐fold increase ing_absand a 4272‐fold increase in CD. Based on computational analysis, it is concluded that the local plasmon field enhancement around the crevices and tips of nanostars is mainly responsible for the observed effect which is further supported by a signal enhancement in Surface Enhanced Raman Scattering (SERS). Thus, this study underscores the significant role of close‐range plasmon interactions in altering the chiroptical response of nanocomposite materials and a practical pathway toward the realization of next‐generation integrated photonics and optoelectronic circuitry with photon spin control. 

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3. Impurity Band Formation as a Route to Thermoelectric Power Factor Enhancement in n‐type XNiSn Half‐Heuslers

   https://doi.org/10.1002/apxr.202400179  

   Quinn, Robert J; Go, Yuji; Naden, Aaron B; Bojtor, Andras; Paráda, Gabor; Shawon, Ashiq_K_M A; Domosud, Kamil; Refson, Keith; Zevalkink, Alexandra; Neophytou, Neophytos; et al (January 2025, Advanced Physics Research)

   Abstract Bandstructure engineering is a key route for thermoelectric performance enhancement. Here, 20–50% Seebeck (S) enhancement is reported for XNiCu_ySn half‐Heusler samples based onX= Ti. This novel electronic effect is attributed to the emergence of impurity bands of finite extent, due to the Cu dopants. Depending on the dispersion, extent, and offset with respect to the parent material, these bands are shown to enhanceSto different degrees. Experimentally, this effect is controllable by the Ti content of the samples, with the addition of Zr/Hf gradually removing the enhancement. At the same time, the mobility remains largely intact, enabling power factors ≥3 mW m⁻¹K⁻²near room temperature, increasing to ≥5 mW m⁻¹K⁻²at high temperature. Combined with reduced thermal conductivity due to the Cu interstitials, this enables high averagezT= 0.67–0.72 between 320 and 793 K for XNiCu_ySn compositions with ≥70% Ti. This work reveals the existence of a new route for electronic performance enhancement in n‐type XNiSn materials that are normally limited by their single carrier pocket. In principle, impurity bands can be applied to other materials and provide a new direction for further development. 

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4. Synthesis of a BINOL‐Based C ₃ Symmetric Schiff Base and Its Fluorescence Response to Zn ²⁺

   https://doi.org/10.1002/cplu.202300036  

   Lu, Kai; Guo, Hongyu; Jiang, Yixuan; Yang, Jiaqiao; Yu, Shanshan; Yu, Xiaoqi; Pu, Lin (March 2023, ChemPlusChem)

   Abstract A novelC₃symmetric 1,1’‐bi‐2‐naphthol‐based Schiff base (R,R,R)‐6has been synthesized which shows highly selective fluorescence enhancement with Zn²⁺among 21 metal cations examined. Its sensitivity and selectivity are found to be greater than other relatedC₂(1) andC₁[(R)‐9] symmetric compounds in the fluorescent recognition of Zn²⁺. The mechanistic study reveals that the selective fluorescence enhancement of the probe can be attributed to the formation of a unimolecular multidentate 6‐coordinated Zn²⁺complex. 

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5. Increased Photostability of the Integral mRNA Vaccine Component N ₁ ‐Methylpseudouridine Compared to Uridine

   https://doi.org/10.1002/chem.202103667  

   Hoehn, Sean_J; Krul, Sarah_E; Skory, Brandon_J; Crespo‐Hernández, Carlos_E (December 2021, Chemistry – A European Journal)

   Abstract N₁‐Methylation of pseudouridine (m¹ψ) replaces uridine (Urd) in several therapeutics, including the Moderna and BioNTech‐Pfizer COVID‐19 vaccines. Importantly, however, it is currently unknown if exposure to electromagnetic radiation can affect the chemical integrity and intrinsic stability of m¹ψ. In this study, the photochemistry of m¹ψ is compared to that of uridine by using photoirradiation at 267 nm, steady‐state spectroscopy, and quantum‐chemical calculations. Furthermore, femtosecond transient absorption measurements are collected to delineate the electronic relaxation mechanisms for both nucleosides under physiologically relevant conditions. It is shown that m¹ψ exhibits a 12‐fold longer¹ππ* decay lifetime than uridine and a 5‐fold higher fluorescence yield. Notably, however, the experimental results also demonstrate that most of the excited state population in both molecules decays back to the ground state in an ultrafast time scale and that m¹ψ is 6.7‐fold more photostable than Urd following irradiation at 267 nm. 

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