For over a decade there has been some significant excitement and speculation that quantum effects may be important in the excitation energy transport process in the light harvesting complexes of certain bacteria and algae, in particular via the Fenna-Matthews-Olsen (FMO) complex. Whilst the excitement may have waned somewhat with the realisation that the observed long-lived oscillations in two-dimensional electronic spectra of FMO are probably due to vibronic coherences, it remains a question whether these coherences may play any important role. We review our recent work showing how important the site-to-site variation in coupling between chloroplasts in FMO and their protein scaffold environment is for energy transport in FMO and investigate the role of vibronic modes in this transport. Whilst the effects of vibronic excitations seem modest for FMO, we show that for bilin-based pigment-protein complexes of marine algae, in particular PC645, the site-dependent vibronic excitations seem essential for robust excitation energy transport, which may again open the door for important quantum effects to be important in these photosynthetic complexes.
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http://dx.doi.org/10.1039/c9fd00081j | DOI Listing |
ACS Nano
January 2025
Sauvage Laboratory for Smart Materials, School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China.
With the potential to surpass the Shockley-Queisser (S-Q) limitation for solar energy conversion, the bulk photovoltaic (BPV) effect, which is induced by the broken inversion symmetry of the lattice, presents prospects for future light-harvesting technologies. However, the development of BPV is largely limited by the low solar spectrum conversion efficiency of existing noncentrosymmetric materials with wide band gaps. This study reports that the strain-induced reduction of inversion symmetry can enhance the second-order nonlinear susceptibility (χ) of SnPSe crystals by an order of magnitude, which contributes to an extremely high value of 1.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States.
Lead-free halide double perovskites (DPs) have become a research hotspot in the field of photoelectrons due to their unique optical properties and flexible compositional tuning. However, the luminescence of DPs exhibits thermal quenching at high temperatures, which severely affects their further application. Herein, we synthesized the rare earth Dy and transition metal Mn codoped CsNaYCl rare earth DPs and characterized the optical properties using temperature-dependent photoluminescence spectra and time-resolved photoluminescence decay profiles at different temperatures.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Institute of Nano Science and Technology, Sector 81, Knowledge City, Manauli, Mohali, Mohali, Punjab, 140306, INDIA.
Two-dimensional (2D) materials hold great promise for the next-generation optoelectronics applications, many of which, including solar cell, rely on the efficient dissociation of exciton into free charge carriers. However, photoexcitation in atomically thin 2D semiconductors typically produces exciton with a binding energy of ~500 meV, an order of magnitude larger than thermal energy at room temperature. This inefficient exciton dissociation can limit the efficiency of photovoltaics.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Department of Physics, Kent State University, 008 Smith Hall, Kent, Ohio, 44240, UNITED STATES.
We consider a problem of nonlinear response to an external electromagnetic radiation in conventional disordered superconductors which contain a small amount of weak magnetic impurities. We focus on the diffusive limit and use Usadel equation to analyze the excitation energy and dispersion relation of the collective modes. We determine the resonant frequency and dispersion of both amplitude (Schmidt-Higgs) and phase (Carlson-Goldman) modes for moderate strength of magnetic scattering.
View Article and Find Full Text PDFRev Sci Instrum
January 2025
University of Dayton Research Institute, Dayton, Ohio 45469, USA.
A method to determine electron temperature within a plasma by the spectral analysis of atomic tungsten emission has been explored. The technique was applied to a post-discharge region immediately following a high voltage nanosecond pulsed discharge in air with tungsten electrodes. Atomic tungsten lines are readily observed in the weak emission spectrum within the post-discharge region for many microseconds.
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