We present a comparative study of two self-assembled quantum dot (QD) systems based on II-VI compounds: CdTe/ZnTe and CdSe/ZnSe. Using magneto-optical techniques we investigated a large population of individual QDs. The systematic photoluminescence studies of emission lines related to the recombination of neutral exciton X, biexciton XX, and singly charged excitons (X(+), X(-)) allowed us to determine average parameters describing CdTe QDs (CdSe QDs): X-XX transition energy difference 12 meV (24 meV); fine-structure splitting δ1=0.14 meV (δ1=0.47 meV); g-factor g = 2.12 (g = 1.71); diamagnetic shift γ=2.5 μeV T(-2) (γ =1.3 μeV T(-2)). We find also statistically significant correlations between various parameters describing internal structure of excitonic complexes.
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http://dx.doi.org/10.1088/0953-8984/28/26/265302 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Sun Yat-Sen University, School of Chemistry and Chemical Engineering, 135 West Xingang Road, 510275, Guangzhou, CHINA.
Metal-organic complexes with long afterglow luminescence have attracted extensive attention due to potential applications in display, sensing and information security. However, most of the metal-organic complex long afterglow materials reported so far are limited to the use of UV light as the excitation source, and the ambiguity of the structure-activity relationship makes the development of metal-organic complexes extremely limited. Herein, a series of metal-organic complexes with ultralong emission lifetime is constructed by coordination assembly of Zn(II) with three isomers.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
Modulation of optical properties through smart protein matrices is exemplified by a few examples in nature such as rhodopsin (absorption wavelength tuning) and the green fluorescence protein (emission), but in general, the scope found in nature for the matrix-controlled photofunctions remains rather limited. In this review, we present cyclophane-based supramolecular host-guest complexes for which electronic interactions between the cyclophane host and mostly planar aromatic guest molecules can actively modulate excited-state properties in a more advanced way involving both singlet and triplet excited states. We begin by highlighting photofunctional host-guest systems for on-off fluorescence switching and chiroptical functions using bay-functionalized perylene bisimide cyclophanes.
View Article and Find Full Text PDFBiophys J
January 2025
Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom. Electronic address:
Photosynthetic organisms rely on a network of light-harvesting protein-pigment complexes to efficiently absorb sunlight and transfer excitation energy to reaction centre proteins where charge separation occurs. In photosynthetic purple bacteria, these complexes are embedded within the cell membrane, with lipid composition affecting complex clustering, thereby impacting inter-complex energy transfer. However, the impact of the lipid bilayer on intra-complex excitation dynamics is less understood.
View Article and Find Full Text PDFACS Nano
January 2025
Beijing Academy of Quantum Information Sciences, Beijing 100193, P. R. China.
The quantum-well-like two-dimensional lead-halide perovskites exhibit strongly confined excitons due to the quantum confinement and reduced dielectric screening effect, which feature intriguing excitonic effects. The ionic nature of the perovskite crystal and the "softness" of the lattice induce the complex lattice dynamics. There are still open questions about how the soft lattices decorate the nature of excitons in these hybrid materials.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China.
Perovskite quantum dots (QDs) are high-efficiency optoelectronic materials attracting great interest, but further improvement in the luminescence efficiency is crucial for their application. In this work, we enhance both the spontaneous emission rate and the photoluminescence (PL) intensity of CsPbBr QDs by coupling them to a high quality () factor SiO microdisk cavity. Compared to conventional metal plasmonic cavities, the dielectric cavity structure suppresses the effects of quenching and energy transfer, which could introduce complex fluctuations and nonradiative decays.
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