The work function of n-alkanethiol self-assembled monolayers (SAMs) prepared on the GaAs(001) surface was measured using the Kelvin probe technique yielding the SAM 2D dipole layer potential (DLP). Direct n-dependent proportionality between the DLP values and the C-H stretching mode infrared (IR) absorption intensities was observed, which supports a correspondence of reported IR enhancements with the electrostatic properties of the interface. X-ray photoelectron spectroscopy is also used to verify the work function measurements. In addition, the principal components of the refractive index tensor are shown to be n-invariant in the ordered SAM phase. Our results suggest that a local field correction to the transition dipole moment accounts for the observed increase in IR activity through an increase to the electronic polarizability.
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January 2025
College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310058, China.
J Phys Chem B
January 2025
Institut für Physik, Universität Augsburg, 86159 Augsburg, Germany.
The alignment of permanent dipole moments and the resulting spontaneous orientation polarization (SOP) are commonly observed in evaporated neat films of polar organic molecules and lead to a so-called giant surface potential. In the case of mixed films, often enhanced molecular orientation is observed, i.e.
View Article and Find Full Text PDFNat Commun
December 2024
Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.
Extending ferroelectric materials to two-dimensional limit provides versatile applications for the development of next-generation nonvolatile devices. Conventional ferroelectricity requires materials consisting of at least two constituent elements associated with polar crystalline structures. Monolayer graphene as an elementary two-dimensional material unlikely exhibits ferroelectric order due to its highly centrosymmetric hexagonal lattices.
View Article and Find Full Text PDFMembranes (Basel)
December 2024
Institute of Physics, Opole University, Oleska 48, 45-052 Opole, Poland.
This article investigates the influence of dopant molecules on the structural and dynamic properties of lipid bilayers in liposomes, with a focus on the effects of dopant concentration, size, and introduced electric charge. Experimental studies were performed using electron paramagnetic resonance (EPR) spectroscopy with spin probes, complemented by Monte Carlo simulations. Liposomes, formed via lecithin sonication, were doped with compounds of varying concentrations and analyzed using EPR spectroscopy to assess changes in membrane rigidity.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
College of Science, Inner Mongolia University of Technology, Hohhot 010051, China.
Relaxor ferroelectric film capacitors exhibit high power density with ultra-fast charge and discharge rates, making them highly advantageous for consumer electronics and advanced pulse power supplies. The Aurivillius-phase bismuth layered ferroelectric films can effectively achieve a high breakdown electric field due to their unique insulating layer ((BiO) layer)). However, designing and fabricating Aurivillius-phase bismuth layer relaxor ferroelectric films with optimal energy storage characteristics is challenging due to their inherently stable ferroelectric properties.
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