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The room-temperature charge carrier mobility and excitation-emission properties of metal halide perovskites are governed by their electronic band structures and intrinsic lattice phonon scattering mechanisms. Establishing how charge carriers interact within this scenario will have far-reaching consequences for developing high-efficiency materials for optoelectronic applications. Herein we evaluate the charge carrier scattering properties and conduction band environment of the double perovskite CsAgBiBr via a combinatorial approach; single crystal X-ray diffraction, optical excitation and temperature-dependent emission spectroscopy, resonant and nonresonant Raman scattering, further supported by first-principles calculations. We identify deep conduction band energy levels and that scattering from longitudinal optical phonons- via the Fröhlich interaction-dominates electron scattering at room temperature, manifesting within the nominally nonresonant Raman spectrum as multiphonon processes up to the fourth order. A Fröhlich coupling constant nearing 230 meV is inferred from a temperature-dependent emission line width analysis and is found to be extremely large compared to popular lead halide perovskites (between 40 and 60 meV), highlighting the fundamentally different nature of the two "single" and "double" perovskite materials branches.
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http://dx.doi.org/10.1021/acsnano.8b02936 | DOI Listing |
Environ Geochem Health
September 2025
Department of Chemistry, Government Arts College(A), Salem, Tamil Nadu, 636007, India.
A CoO/AgMoO/CeOternary nanocomposites photocatalyst was successfully synthesized through a straightforward ethanol-assisted chemical method. Comprehensive characterization of its structural and optical properties was conducted using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (UV-DRS), and photoluminescence (PL) analysis. XRD analysis confirmed the presence of CoO, AgMoO and CeO in the ternary composite sample.
View Article and Find Full Text PDFJ Neurosci
September 2025
Department of Bioengineering, George Mason University, Fairfax, VA, United States,
In the hippocampal formation, cholinergic modulation from the medial septum/diagonal band of Broca (MSDB) is known to correlate with the speed of an animal's movements at sub-second timescales and also supports spatial memory formation. Yet, the extent to which sub-second cholinergic dynamics, if at all, align with transient behavioral and cognitive states supporting the encoding of novel spatial information remains unknown. In this study, we used fiber photometry to record the temporal dynamics in the population activity of septo-hippocampal cholinergic neurons at sub-second resolution during a hippocampus-dependent object location memory task using ChAT-Cre mice of both sexes.
View Article and Find Full Text PDFJ Mol Graph Model
September 2025
Department of Physics, Patan Multiple Campus, Tribhuvan University, Patandhoka, Lalitpur, 44700, Bagmati, Nepal; Department of Physics, St. Xavier's College, Maitighar, Bagmati, 44600, Kathmandu, Nepal. Electronic address:
The bioactive organosulfur compound diallyl sulfide (DAS), found in garlic and onions, was analyzed using density functional theory (DFT). DAS exhibits antimicrobial and anticancer properties, making it a potential candidate for drug discovery. Geometry optimization revealed bond lengths and angles consistent with electron delocalization.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
Huazhong University of Science and Technology, Wuhan National Laboratory for Optoelectronics and School of Physics, Wuhan 430074, China.
We propose a scheme for retrieving the ultrafast valley polarization (VP) dynamics in two-dimensional hexagonal materials via attosecond circular dichroism (CD) transient absorption spectroscopy. This approach builds on the CD transition between the first and higher conduction bands induced by the circularly polarized probe pulses. The population imbalance at nonequivalent valleys in the first conduction band is proportionally mapped onto the difference in absorption coefficients of two probe pulses with opposite helicities, supporting an unprecedented quantitative retrieval of the corresponding VP dynamics with subfemtosecond time resolution.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
Princeton University, Department of Physics, Princeton, New Jersey 08544, USA.
We define the absolute Wilson loop winding and prove that it bounds the (integrated) quantum metric from below. This Wilson loop lower bound naturally reproduces the known Chern and Euler bounds of the integrated quantum metric and provides an explicit lower bound of the integrated quantum metric due to the time-reversal protected Z_{2} index, answering a hitherto open question. In general, the Wilson loop lower bound can be applied to any other topological invariants characterized by Wilson loop winding, such as the particle-hole Z_{2} index.
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