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Precisely doped metal nanoclusters (NCs) are currently emerging nanomaterials for their unique photophysical properties. Here, we report the influence of single atom doping on the excited state relaxation dynamics of a series of MAg(2,4-MePhS) NCs where M is Ag, Au, Pd, and Pt. The NCs with a group 11 metal (Ag and Au) as central atoms exhibit dual emission at NIR and visible range, whereas it shows only NIR emission for group 10 metal (Pd and Pt) doped NCs. Global target analyses of transient absorption (TA) data reveal the three-state relaxation, i.e., initially excited state (S), ligand-centered charge transfer (CT) state (S), and metal-centered lowest excited state (S). Apart from the HOMO-LUMO (H-L) energy gap, the electron affinity of the central metal atom and rigidity of the NC structural framework influence the relaxation processes of the NCs. The extensive study into the relaxation dynamics will bestow the single atomic level modulation of photophysical properties.
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http://dx.doi.org/10.1021/acs.jpclett.2c01333 | DOI Listing |
J Math Biol
September 2025
School of Mathematical Sciences and Institute of Natural Sciences, MOE-LSC, CMA-Shanghai, Shanghai Jiao Tong University, Shanghai, China.
It has been noticed that when the waiting time distribution exhibits a transition from an intermediate time power-law decay to a long-time exponential decay in the continuous time random walk model, a transition from anomalous diffusion to normal diffusion can be observed at the population level. However, the mechanism behind the transition of waiting time distribution is rarely studied. In this paper, we provide one possible mechanism to explain the origin of such a transition.
View Article and Find Full Text PDFACS Nano
September 2025
College of Materials Science and Engineering, Fuzhou University, Fuzhou 350108, China.
Polymorphic two-dimensional (2D) transition metal dichalcogenides (TMDCs) exhibit diverse properties for optoelectronic applications. Here, utilizing phase-engineered MoTe as a prototypical platform, we comprehensively explored its ultrafast and nonlinear optical properties to complete the fundamental framework of phase-dependent optical phenomena in 2D TMDCs. Starting with the phase-selective synthesis of 2H- and 1T'-MoTe with tailored thicknesses, we revealed their distinct photocarrier relaxation mechanisms using intensive power-/temperature-/thickness-dependent transient absorption spectra (TAS).
View Article and Find Full Text PDFBehav Brain Res
September 2025
Faculty of Human Sciences, Waseda University, 2‑579‑15 Mikajima, Tokorozawa, Saitama, Japan. Electronic address:
Insight problem solving involves overcoming an impasse when a solution seems unreachable, often experienced as an 'Aha!' moment. In such solving, shifting from an incorrect representation imposed by constraints to a correct representation through constraint relaxation is critical. Prior research compared brain activity when constraint relaxation and representation change occurred versus when they did not occur, but neural activity before and after such changes within trials has remained underexplored.
View Article and Find Full Text PDFChem Soc Rev
September 2025
State Key Laboratory of Crystal Materials, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
Understanding the excited-state dynamics of atomically precise coinage metal nanoclusters (CMNCs) is pivotal for elucidating their photoluminescence (PL) mechanisms and rationally tuning emission properties-particularly in the near-infrared (NIR) region, where CMNC-based nanomaterials have tremendous potential for biomedical and optoelectronic applications. This review presents a systematic and comprehensive account of recent advances in investigating the excited-state dynamics and PL mechanisms of NIR-emitting CMNCs with atomic precision, leveraging the synergistic integration of time-resolved spectroscopy and time-dependent density functional theory (TD-DFT) calculations. Distinct from previous reviews that offer a broad survey of CMNC properties, the present review focuses specifically on intrinsic factors, highlighting molecular vibrational features and electronic structure modulation as key determinants of NIR emission.
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States.
Carbon dots (CDs) represent a new class of nontoxic and sustainable nanomaterials with increasing applications. Among them, bright and large Stokes-shift CDs are highly desirable for display and imaging, yet the emission mechanisms remain unclear. We obtained structural signatures for the recently engineered green and red CDs by ground-state femtosecond stimulated Raman spectroscopy (FSRS), then synthesized orange CDs with similar size but much higher nitrogen dopants than red CDs.
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