This article reviews the mechanisms through which molecules adsorbed to the surfaces of semiconductor nanocrystals, quantum dots (QDs), influence the pathways for and dynamics of intra- and interband exciton relaxation in these nanostructures. In many cases, the surface chemistry of the QDs determines the competition between Auger relaxation and electronic-to-vibrational energy transfer in the intraband cooling of hot carriers, and between electron or hole-trapping processes and radiative recombination in relaxation of band-edge excitons. The latter competition determines the photoluminescence quantum yield of the nanocrystals, which is predictable through a set of mostly phenomenological models that link the surface coverage of ligands with specific chemical properties to the rate constants for nonradiative exciton decay.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1146/annurev-physchem-040513-103649 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Coherent Exciton Spin Relaxation Dynamics and Exciton Polaron Character in Layered Two-Dimensional Lead-Halide Perovskites.
ACS 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 PDFLight-Harvesting Spin Hyperpolarization of Organic Radicals in a Metal-Organic Framework.
J Am Chem Soc
January 2025
Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Light-driven spin hyperpolarization of organic molecules is a crucial technique for spin-based applications such as quantum information science (QIS) and dynamic nuclear polarization (DNP). Synthetic chemistry provides the design of spins with atomic precision and enables the scale-up of individual spins to hierarchical structures. The high designability and extended pore structure of metal-organic frameworks (MOFs) can control interactions between spins and guest molecules.
View Article and Find Full Text PDFSymmetry-Breaking Charge-Separation in a Subphthalocyanine Dimer Resolved by Two-Dimensional Electronic Spectroscopy.
J Phys Chem C Nanomater Interfaces
January 2025
School of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K.
Understanding the role of structural and environmental dynamics in the excited state properties of strongly coupled chromophores is of paramount importance in molecular photonics. Ultrafast, coherent, and multidimensional spectroscopies have been utilized to investigate such dynamics in the simplest model system, the molecular dimer. Here, we present a half-broadband two-dimensional electronic spectroscopy (HB2DES) study of the previously reported ultrafast symmetry-breaking charge separation (SB-CS) in the subphthalocyanine oxo-bridged homodimer μ-OSubPc.
View Article and Find Full Text PDFIdentification of Two-Dimensional Interlayer Excitons and Their Valley Polarization in MoSe/WSe Heterostructure with -BN Spacer Layer.
ACS Nano
January 2025
Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan.
Interlayer excitons (IXs) in the heterostructure of monolayer transition metal dichalcogenides (TMDs) are considered as a promising platform to study fundamental exciton physics and for potential applications of next generation optoelectronic devices. The IXs trapped in the moiré potential in a twisted monolayer TMD heterostructure such as MoSe/WSe form zero-dimensional (0D) moiré excitons. Introducing an atomically thin insulating layer between TMD monolayers in a twisted heterostructure would modulate the moiré potential landscape, thereby tuning 0D IXs into 2D IXs.
View Article and Find Full Text PDFMethacrylate-based copolymers as tunable hosts for triplet-triplet annihilation upconversion.
Mater Adv
January 2025
Department of Materials Science and Metallurgy, University of Cambridge CB3 0FS UK
The ability to convert light to higher energies through triplet-triplet annihilation upconversion (TTA-UC) is attractive for a range of applications including solar energy harvesting, bioimaging and anti-counterfeiting. Practical applications require integration of the TTA-UC chromophores within a suitable host, which leads to a compromise between the high upconversion efficiencies achievable in liquids and the durability of solids. Herein, we present a series of methacrylate copolymers as TTA-UC hosts, in which the glass transition temperature ( ), and hence upconversion efficiency can be tuned by varying the co-monomer ratios (-hexyl methacrylate (HMA) and 2,2,2-trifluoroethyl methacrylate (TFEMA)).
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!