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A previously developed semiclassical theory of nonadiabatic energy transfer is used to analyze electronic excitation and quenching in three-dimensional atomic collisions. The predicted transition probabilities, cross sections, and rate coefficients are compared with the quantum scattering calculations for O + O and N + N, for the same interaction potentials and nonadiabatic coupling, and with the experimental data where available. The theory predictions are in very good agreement with quantum scattering, at the conditions when the energy transfer is dominated by a single pair of adiabatic potentials. Closed-form analytic expressions for the cross sections and rate coefficients are obtained, for both the strongly and weakly coupled cases. The results quantify and illustrate the effect of the interaction potentials and their coupling on the energy transfer. The analytic cross sections and rate coefficients are in good agreement with the numerical predictions. The same approach has been used to predict the rate coefficients of electronic excitation and quenching in collisions of N + O atoms. The fidelity of these predictions may be improved considerably if accurate potentials for the excited electronic states of N + O and their coupling are available. The applicability of the semiclassical theory for the prediction of the rates of heavy particle impact excitation in atom–molecule collisions is discussed. [ABSTRACT FROM AUTHOR]

Metal ion-induced water pollution is attracting increasing public attention. Perovskite quantum dots and metal–organic frameworks (MOFs), owing to their outstanding properties, hold promise as ideal probes for detecting metal ions. In this study, a composite material, MAPbBr3@PCN-221(Fe), was prepared by encapsulating MAPbBr3 quantum dots with PCN-221(Fe), demonstrating high chemical stability and good reusability. The composite material shows a sensitive fluorescence turn-on signal in the presence of silver ions. The fluorescence intensity of the composite material exhibits a linear relationship with the concentration of Ag+ in the solution, with a low detection limit of 8.68 µM. Moreover, the fluorescence signal exhibits a strong selectivity for Ag+, enabling the detection of Ag+ concentration. This fluorescence turn-on signal originates from the Ag+-bridged energy transfer from the conductive band of MAPbBr3 to the excited state of the MOF, which is directly proportional to the concentration of silver ions. Simultaneously, this finding may open up a new possibility in artificial controlled energy transfer from perovskite to MOF for future development. [ABSTRACT FROM AUTHOR]

Environmental effects in excitation energy transfer have mostly been modeled by baths of harmonic oscillators, but to what extent such modeling provides a reliable description of actual interactions between molecular systems and environments remains an open issue. We address this issue by investigating fluctuations in the excitation energies of the light harvesting 2 complex using a realistic all-atomistic simulation of the potential energy surface. Our analyses reveal that molecular motions exhibit significant anharmonic features, even for underdamped intramolecular vibrations. In particular, we find that the anharmonicity contributes to the broadening of spectral densities and substantial overlaps between neighboring peaks, which complicates the meaning of mode frequencies constituting a bath model. Thus, we develop a strategy to construct a minimally underdamped harmonic bath that has a clear connection to all-atomistic dynamics by utilizing actual normal modes of molecules but optimizing their frequencies such that the resulting bath model can best reproduce the all-atomistic simulation results. By subtracting the underdamped contribution from the entire fluctuations, we also show that identifying a residual spectral density representing all other contributions with overdamped behavior is possible. We find that this can be fitted well with a well-established analytic form of a spectral density function or, alternatively, modeled as explicit time dependent fluctuations with muti-exponential or power law type correlation functions. We provide an assessment and the implications of these possibilities. The approach presented here can also serve as a general strategy to construct a simplified bath model that can effectively represent the underlying all-atomistic bath dynamics. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of photoinduced processes in complex systems is crucial for the development of advanced energy-conversion materials. In this study, we investigate the nonadiabatic dynamics using time-convolution (TC) and time-convolutionless (TCL) quantum master equations (QMEs) based on treating electronic couplings as perturbation within the framework of multistate harmonic (MSH) models. The MSH model Hamiltonians are mapped from all-atom simulations such that all pairwise reorganization energies are consistently incorporated, leading to a heterogeneous environment that couples to the multiple electronic states differently. Our exploration encompasses the photoinduced charge transfer dynamics in organic photovoltaic carotenoid–porphyrin–C60 triad dissolved in liquid solution and the excitation energy transfer (EET) dynamics in photosynthetic Fenna–Matthews–Olson complexes. By systematically comparing the perturbative TC and TCL QME approaches with exact quantum-mechanical and various semiclassical approximate kernels, we demonstrate their efficacy and accuracy in capturing the essential features of photoinduced dynamics. Our calculations show that TC QMEs generally yield more accurate results than TCL QMEs, especially in EET, although both methods offer versatile approaches adaptable across different systems. In addition, we investigate various semiclassical approximations featuring the Wigner-transformed and classical nuclear densities as well as the governing dynamics during the quantum coherence period, highlighting the trade-off between accuracy and computational cost. This work provides valuable insights into the applicability and performance of TC and TCL QME approaches via the MSH model, offering guidance for realistic applications to condensed-phase systems on the atomistic level. [ABSTRACT FROM AUTHOR]

In the studies of the vulnerability of armored vehicles, the impact of high-velocity penetrators on liquid-filled container components is one of the critical concerns. The purpose of this study is to investigate the structural damage of the liquid-filled container subjected to shaped charge jet impact utilizing the Structural Arbitrary Lagrangian–Eulerian method in ANSYS/LS-DYNA. The numerical model is validated against available experimental data. The validation effort of the numerical model showed very good agreements with experiments in terms of radial shock wave and radial crater formation as a function of time. Using the validated model, the liquid pressure, the energy transfer as well as the influence of overmatch on the impact process were analyzed. The results indicate that the structural damage modes of containers under shaped charge jet impact include perforation and wall deformation. Perforation results from the penetration of the jet tip and tail, while wall deformation is caused by the high-velocity impact of the flowing liquid. In cases where the overmatch (OM) is equal to 1, the contribution of the tip to front and back wall perforation increment primarily depends on the impact velocity. In cases with OM less than 1, the "filtering effect" of the Rolled Homogeneous Armor (RHA) armor plate leads to the loss of the tail's contribution to front wall perforation. [ABSTRACT FROM AUTHOR]

In photodynamic therapy (PDT) treatment, heavy-atom-free photosensitizers (PSs) are a great source of singlet oxygen photosensitizer. Reactive oxygen species (ROS) are produced by an energy transfer from the lowest energy triplet excited state to the molecular oxygen of cancer cells. To clarify the photophysical characteristics in the excited states of a few experimentally identified thionated (>C=S) molecules and their oxygenated congeners (>C=O), a quantum chemical study is conducted. This study illustrates the properties of the excited states in oxygen congeners that render them unsuitable for PDT treatment. Concurrently, a hierarchy is presented based on the utility of the lowest-energy triplet excitons of thionated compounds. Their non-radiative decay rates are calculated for reverse-ISC and inter-system crossover (ISC) processes. In addition, the vibronic importance of C=O and C=S bonds is clarified by the computation of the Huang–Rhys factor, effective vibrational mode, and reorganization energy inside the Marcus–Levich–Jörtner system. ROS generation in thionated PSs exceeds their oxygen congeners as kf ≪ kISC, where radiative decay rate is designated as kf. As a result, the current work offers a calculated strategy for analyzing the effectiveness of thionated photosensitizers in PDT. [ABSTRACT FROM AUTHOR]

We study a moving adsorbate interacting with a metal electrode immersed in a solvent using the time-dependent Newns–Anderson–Schmickler model Hamiltonian. We have adopted a semiclassical trajectory treatment of the adsorbate to discuss the electron and energy transfers that occur between the adsorbate and the electrode. Using Keldysh Green's function scheme, we found a non-adiabatically suppressed electron transfer caused by the motion of the adsorbate and coupling with bath phonons that model the solvent. The energy is thus dissipated into electron–hole pair excitations, which are hindered by interacting with the solvent modes and facilitated by the applied electrode potential. The average energy transfer rate is discussed in terms of the electron friction coefficient and given an analytical expression in the slow-motion limit. [ABSTRACT FROM AUTHOR]

The light-harvesting excitonic properties of poly(phenylene ethynylene) (PPE) extended dendrimers (tree-like π-conjugated macromolecules) involve a directional cascade of local excitation energy transfer (EET) processes occurring from the "leaves" (shortest branches) to the "trunk" (longest branch), which can be viewed from a vibronic perspective as a sequence of internal conversions occurring among a connected graph of nonadiabatically coupled locally excited electronic states via conical intersections. The smallest PPE building block that is able to exhibit EET, the asymmetrically meta-substituted PPE oligomer with one acetylenic bond on one side and two parallel ones on the other side (hence, 2-ring and 3-ring para-substituted pseudo-fragments), is a prototype and the focus of the present work. From linear-response time-dependent density functional theory electronic-structure calculations of the molecule as regards its first two nonadiabatically coupled, optically active, singlet excited states, we built a (1 + 2)-state-8-dimensional vibronic-coupling Hamiltonian model for running subsequent multiconfiguration time-dependent Hartree wavepacket relaxations and propagations, yielding both steady-state absorption and emission spectra as well as real-time dynamics. The EET process from the shortest branch to the longest one occurs quite efficiently (about 80% quantum yield) within the first 25 fs after light excitation and is mediated vibrationally through acetylenic and quinoidal bond-stretching modes together with a particular role given to the central-ring anti-quinoidal rock-bending mode. Electronic and vibrational energy relaxations, together with redistributions of quantum populations and coherences, are interpreted herein through the lens of a nonadiabatic perspective, showing some interesting segregation among the foremost photoactive degrees of freedom as regards spectroscopy and reactivity. [ABSTRACT FROM AUTHOR]

A merged potential energy surface (PES) is introduced for CO + CO collisions by combining a recent full-dimensional ab initio PES [Chen et al. J. Chem. Phys. 153, 054310 (2020)] and analytical long-range multipolar interactions. This merged PES offers a double advantage: it retains the precision of the ab initio PES in describing the van der Waals well and repulsive short range while providing an accurate physical description of long-range interaction; it significantly reduces the computational time required for trajectory integration since the long-range portion of the ab initio PES (involving numerous neural network fitting parameters) is now replaced by the analytical model potential. Based on the present merged PES, mixed Quantum-Classical (MQC) calculations, which capture quantum effects related to vibrational motion, align with a range of experimental data, including transport properties, vibrational energy transfer between CO and its isotoplogues, as well as rate coefficients for V–V and V–T/R processes. Notably, the original ab initio PES yields V–T/R rate coefficients at low temperatures that are significantly higher than the experimental data due to the artificial contribution of its unphysical long-range potential. In addition to conducting extensive MQC calculations to obtain raw data for V–V and V–T/R rate coefficients, we employ Gaussian process regression to predict processes lacking computed MQC data, thereby completing the considered V–V and V–T/R datasets. These extensive rate coefficient datasets, particularly for V–T/R processes, are unprecedented and reveal the significant role played by V–T/R processes at high temperatures, emphasizing the necessity of incorporating both V–V and V–T/R processes in the applications. [ABSTRACT FROM AUTHOR]

The entanglement between system and bath often plays a pivotal role in complex systems spanning multiple orders of magnitude. A system–bath entanglement theorem was previously established for Gaussian environments in J. Chem. Phys. 152, 034102 (2020) regarding linear response functions. This theorem connects the entangled responses to the local system and bare bath properties. In this work, we generalize it to correlation functions. Key steps in derivations involve using the generalized Langevin dynamics for hybridizing bath modes and the Bogoliubov transformation that maps the original finite-temperature reservoir to an effective zero-temperature vacuum by employing an auxiliary bath. The generalized theorem allows us to evaluate the system–bath entangled correlations and the bath mode correlations in the total composite space, as long as we know the bare-bath statistical properties and obtain the reduced system correlations. To demonstrate the cross-scale entanglements, we utilize the generalized theorem to calculate the solvation free energy of an electron transfer system with intramolecular vibrational modes. [ABSTRACT FROM AUTHOR]

The microscopic mechanism of the energy transfer in cyclotrimethylene trinitramine (RDX) is of particular importance for the study of the energy release process in high-energy materials. In this work, an effective vibrational Hamiltonian based on normal modes (NMs) has been introduced to study the energy transfer process of RDX. The results suggest that the energy redistribution in RDX can be characterized as an ultrafast process with a time scale of 25 fs, during which the energy can be rapidly localized to the –NNO2 twisting mode (vNNO2), the N–N stretching mode (vN–N), and the C–H stretching mode (vC–H). Here, the vNNO2 and vN–N modes are directly related to the cleavage and dissociation of the N–N bond in RDX and, therefore, can be referred to as "active modes." More importantly, we found that the energy can be rapidly transferred from the vC–H mode to the vNNO2 mode due to their strong coupling. From this perspective, the vC–H mode can be regarded as an "energy collector" that plays a pivotal role in supplying energy to the "active modes." In addition, the bond order analysis shows that the dissociation of the N–N bonds of RDX follows a combined twisting and stretching path along the N–N bond. This could be an illustration of the further exothermic decomposition triggered by the accumulation of vibrational energy. The present study reveals the microscopic mechanism for the vibrational energy redistribution process of RDX, which is important for further investigation of the energy transfer process in high-energy materials. [ABSTRACT FROM AUTHOR]

Energy transfer has been proven to be an effective method to optimize optoelectronic conversion efficiency by improving light absorption and mitigating nonradiative losses. We prepared 2D/3D CsPbBr3 hybrid assemblies at different reaction temperatures using the hot injection method and found that the photoluminescence quantum yields (PLQYs) of these hybrids were greatly enhanced from 53.4% to 72.57% compared with 3D nanocrystals (NCs). Femtosecond transient absorption measurements were used to study the PLQY enhancement mechanisms, and it was found that the hot carrier lifetime improved from 0.36 to 1.88 ps for 2D/3D CsPbBr3 hybrid assemblies owing to the energy transfer from 2D nanoplates to 3D NCs. The energy transfer benefits the excited carrier accumulation and prolonged hot carrier lifetime in 3D NCs in hybrid assemblies, as well as PLQY enhancement in materials. [ABSTRACT FROM AUTHOR]

Fluorescent emitters are quenched near the surfaces of metals via rapid energy transfer to the metal, via surface plasmons, waveguide modes, and absorption. Commonly, this quenching is reduced by introducing a polymeric or dielectric spacer but requires large distances, at least a fraction of the wavelength, between the metal and chromophore. Using the classical theory for a dipole above a metal/dielectric substrate, we investigate the fluorescent yield for emitters above a wide range of metals and spacers. For metals with low loss and low plasma frequencies, a high index spacer is shown to be advantageous for obtaining higher fluorescent yield in an "island of emission" at finely tuned spacer thickness just 20–30 nm from the metal surface. For such metal–dielectric combinations, fluorophores can be placed surprisingly close to the metal surface while remaining significantly emissive. [ABSTRACT FROM AUTHOR]

Inelastic scattering between gas molecules and surfaces is a fundamental process that has been investigated extensively. In recent gas-surface scattering experiments [Phys. Chem. Chem. Phys. 19, 19904 (2017)] on formaldehyde scattering off the gold surface, the scattered formaldehyde molecules had a high propensity to excite twirling motion about the C–O bond. In the work presented here, we used classical dynamics simulations to understand energy transfer in formaldehyde–surface collisions and to probe the mechanism of interconversion of translational energy to rotational energy. The simulations reveal an increase in the rotational energy distribution with an increase in collision energies and a preferential rotational excitation about the C–O bond consistent with the experiments. The high propensity to excite the twirling motion was found to arise from a steering motion about the C–O bond during the scattering process governed by the minimum energy path. [ABSTRACT FROM AUTHOR]

The dynamics of delocalized excitons in light-harvesting complexes (LHCs) can be investigated using different experimental techniques, and transient absorption (TA) spectroscopy is one of the most valuable methods for this purpose. A careful interpretation of TA spectra is essential for the clarification of excitation energy transfer (EET) processes occurring during light-harvesting. However, even in the simplest LHCs, a physical model is needed to interpret transient spectra as the number of EET processes occurring at the same time is very large to be disentangled from measurements alone. Physical EET models are commonly built by fittings of the microscopic exciton Hamiltonians and exciton-vibrational parameters, an approach that can lead to biases. Here, we present a first-principles strategy to simulate EET and transient absorption spectra in LHCs, combining molecular dynamics and accurate multiscale quantum chemical calculations to obtain an independent estimate of the excitonic structure of the complex. The microscopic parameters thus obtained are then used in EET simulations to obtain the population dynamics and the related spectroscopic signature. We apply this approach to the CP29 minor antenna complex of plants for which we follow the EET dynamics and transient spectra after excitation in the chlorophyll b region. Our calculations reproduce all the main features observed in the transient absorption spectra and provide independent insight on the excited-state dynamics of CP29. The approach presented here lays the groundwork for the accurate simulation of EET and unbiased interpretation of transient spectra in multichromophoric systems. [ABSTRACT FROM AUTHOR]

Here, we analyzed the effect of a donor molecule (Rh6G) on the random laser emission of an acceptor molecule (Rh640 perchlorate) coated on the surface of a polymer optical fiber. Due to the energy transfer mechanism, the random lasing threshold of Rh640 perchlorate was found to be reduced in the presence of Rh6G. Also, the emission spectrum of Rh640 perchlorate was blue-shifted with the addition of Rh6G. Meanwhile, there is an enhancement in the lasing threshold of Rh6G in the presence of Rh640 perchlorate. The present study demonstrates that by properly adjusting the concentrations of both donor and acceptor molecules, we can obtain a dual-color random laser emission from polymer optical fiber. [ABSTRACT FROM AUTHOR]

A full-dimensional spin–orbit (SO)-corrected potential energy surface (PES) is developed for the Cl + CH3NH2 multi-channel system. Using the new PES, a comprehensive reaction dynamics investigation is performed for the most reactive hydrogen-abstraction reactions forming HCl + CH2NH2/CH3NH. Hartree–Fock (HF) convergence problems in the reactant region are handled by the ManyHF method, which finds the lowest-energy HF solution considering several different initial guess orbitals. The PES development is carried out with the Robosurfer program package, which iteratively improves the surface. Energy points are computed at the ManyHF-UCCSD(T)-F12a/cc-pVDZ-F12 level of theory combined with basis set (ManyHF-RMP2-F12/cc-pVTZ-F12 – ManyHF-RMP2-F12/cc-pVDZ-F12) and SO (MRCI+Q/aug-cc-pwCVDZ) corrections. Quasi-classical trajectory simulations show that the CH3-side hydrogen abstraction occurs more frequently in contrast to the NH2-side reaction. In both cases, the integral cross sections decrease with increasing collision energy (Ecoll). A reaction mechanism shifting from indirect to direct stripping can be observed from the opacity functions, scattering angle, and translation energy distributions as Ecoll increases. Initial attack angle distributions reveal that chlorine prefers to abstract hydrogen from the approached functional group. The collision-energy dependence of the product energy distributions shows that the initial translational energy mainly transfers to product recoil. The HCl vibrational and rotational energy values are comparable and nearly independent of collision energy, while the CH2NH2 and CH3NH co-products' vibrational energy values are higher than the rotational energy values with more significant Ecoll dependence. The HCl(v = 0) rotational distributions are compared with experiment, setting the direction for future investigations. [ABSTRACT FROM AUTHOR]

The quantum state-to-state rotationally inelastic quenching of N2O by colliding with a He atom is studied on an ab initio potential energy surface with N2O lying on its vibrational ground state. The cross sections for collision energies from 10−6–100 cm−1 and rate constants from 10−5–10 K are calculated employing the fully converged quantum close-coupling method for the quenching of the j = 1–6 rotational states of N2O. Numerous van der Waals shapes or Feshbach resonances are observed; the cross sections of different channels are found to follow the Wigner scaling law in the cold threshold regime and may intersect with each other. In order to interpret the mechanism and estimate the cross sections of the rotational energy transfer, we propose a minimal classical model of collision between an asymmetric double-shell ellipsoid and a point particle. The classical model reproduces the quantum scattering results and points out the attractive interactions and the potential asymmetry can affect the collision process. The resulting insights are expected to expand our interpretations of inelastic scattering and energy transfer in molecular collisions. [ABSTRACT FROM AUTHOR]

Relativistic coupled-cluster calculations of the ionization potential, dissociation energy, and excited electronic states under 35 000 cm−1 are presented for the actinium monofluoride (AcF) molecule. The ionization potential is calculated to be IPe = 48 866 cm−1, and the ground state is confirmed to be a closed-shell singlet and thus strongly sensitive to the T , P -violating nuclear Schiff moment of the Ac nucleus. Radiative properties and transition dipole moments from the ground state are identified for several excited states, achieving a mean uncertainty estimate of ∼450 cm−1 for the excitation energies. For higher-lying states that are not directly accessible from the ground state, possible two-step excitation pathways are proposed. The calculated branching ratios and Franck–Condon factors are used to investigate the suitability of AcF for direct laser cooling. The lifetime of the metastable (1)3Δ1 state, which can be used in experimental searches of the electric dipole moment of the electron, is estimated to be of order 1 ms. [ABSTRACT FROM AUTHOR]

For a detailed understanding of many processes in nature involving, for example, energy or electron transfer, the theory of open quantum systems is of key importance. For larger systems, an accurate description of the underlying quantum dynamics is still a formidable task, and, hence, approaches employing machine learning techniques have been developed to reduce the computational effort of accurate dissipative quantum dynamics. A downside of many previous machine learning methods is that they require expensive numerical training datasets for systems of the same size as the ones they will be employed on, making them unfeasible to use for larger systems where those calculations are still too expensive. In this work, we will introduce a new method that is implemented as a machine-learned correction term to the so-called Numerical Integration of Schrödinger Equation (NISE) approach. It is shown that this term can be trained on data from small systems where accurate quantum methods are still numerically feasible. Subsequently, the NISE scheme, together with the new machine-learned correction, can be used to determine the dissipative quantum dynamics for larger systems. Furthermore, we show that the newly proposed machine-learned correction outperforms a previously handcrafted one, which, however, improves the results already considerably. [ABSTRACT FROM AUTHOR]

We propose a novel UV/Vis femtosecond spectroscopic technique, two-dimensional fluorescence-excitation (2D-FLEX) spectroscopy, which combines spectral resolution during the excitation process with exclusive monitoring of the excited-state system dynamics at high time and frequency resolution. We discuss the experimental feasibility and realizability of 2D-FLEX, develop the necessary theoretical framework, and demonstrate the high information content of this technique by simulating the 2D-FLEX spectra of a model four-level system and the Fenna–Matthews–Olson antenna complex. We show that the evolution of 2D-FLEX spectra with population time directly monitors energy transfer dynamics and can thus yield direct qualitative insight into the investigated system. This makes 2D-FLEX a highly efficient instrument for real-time monitoring of photophysical processes in polyatomic molecules and molecular aggregates. [ABSTRACT FROM AUTHOR]

Hydrophilic semiconductor quantum dots (QDs) with emission in the second near-infrared window (NIR-II) have been widely studied in bioimaging applications. In such cases, QDs are usually dispersed in water. As is known, water has strong absorbance in the NIR-II region. However, investigations on the interaction between NIR-II emitters and water molecules are ignored in previous studies. Herein, we synthesized a series of mercaptoundecanoic acid-coated silver sulfide (Ag2S/MUA) QDs with various emissions that partially or completely overlapped with the absorbance of water at 1200 nm. By constructing a hydrophobic interface of cetyltrimethylammonium bromide (CTAB) with MUA on the Ag2S QDs surface via forming an ionic bond, significant enhancement of Ag2S QDs photoluminescence (PL) intensity was observed, as well as a prolonged lifetime. These findings suggest that there is an energy transfer between Ag2S QDs and water in addition to the classical resonance absorption. Transient absorption and fluorescence spectra results revealed that the increased PL intensities and lifetime of Ag2S QDs originated from the suppressed energy transfer from Ag2S QDs to the water due to the CTAB bridged hydrophobic interfaces. This discovery is important for a deeper understanding of the photophysical mechanisms of QDs and their applications. [ABSTRACT FROM AUTHOR]

Enhancing the utilization of absorbed light is essential for enhancing the efficiency of solar energy conversion via artificial photosynthesis. In this work, we report the successful incorporation of Rhodamine B (RhB) into the pore of ZIF-8 (ZIF = zeolitic imidazolate framework) and the efficient energy transfer process from RhB to Co-doped ZIF-8. Using transient absorption spectroscopy, we show that energy transfer only occurs from RhB (donor) to Co center (acceptor) when RhB is confined into the ZIF-8 structure, which is in stark contrast to the system based on the physical mixture of RhB with Co-doped ZIF-8, where negligible energy transfer was observed. In addition, energy transfer efficiency increases with the concentration of Co and reaches a plateau when the molar ratio of Co to RhB reaches 32. These results suggest that RhB confined in the ZIF-8 structure is essential for energy transfer to occur, and energy transfer efficiency can be controlled by tuning the concentration of acceptors. [ABSTRACT FROM AUTHOR]

The regulation of intramolecular vibrational energy redistribution (IVR) to influence energy flow within molecular scaffolds provides a way to steer fundamental processes of chemistry, such as chemical reactivity in proteins and design of molecular diodes. Using two-dimensional infrared (2D IR) spectroscopy, changes in the intensity of vibrational cross-peaks are often used to evaluate different energy transfer pathways present in small molecules. Previous 2D IR studies of para-azidobenzonitrile (PAB) demonstrated that several possible energy pathways from the N3 to the cyano-vibrational reporters were modulated by Fermi resonance, followed by energy relaxation into the solvent [Schmitz et al., J. Phys. Chem. A 123, 10571 (2019)]. In this work, the mechanisms of IVR were hindered via the introduction of a heavy atom, selenium, into the molecular scaffold. This effectively eliminated the energy transfer pathway and resulted in the dissipation of the energy into the bath and direct dipole–dipole coupling between the two vibrational reporters. Several structural variations of the aforementioned molecular scaffold were employed to assess how each interrupted the energy transfer pathways, and the evolution of 2D IR cross-peaks was measured to assess the changes in the energy flow. By eliminating the energy transfer pathways through isolation of specific vibrational transitions, through-space vibrational coupling between an azido (N3) and a selenocyanato (SeCN) probe is facilitated and observed for the first time. Thus, the rectification of this molecular circuitry is accomplished through the inhibition of energy flow using heavy atoms to suppress the anharmonic coupling and, instead, favor a vibrational coupling pathway. [ABSTRACT FROM AUTHOR]

Resonance energy transfer (RET) is an important and ubiquitous process whereby energy is transferred from a donor chromophore to an acceptor chromophore without contact via Coulombic coupling. There have been a number of recent advances exploiting the quantum electrodynamics (QED) framework for RET. Here, we extend the QED RET theory to investigate whether real photon exchange can allow for excitation transfer over very long distances if the exchanged photon is waveguided. To study this problem, we consider RET in two spatial dimensions. We derive the RET matrix element using QED in two dimensions, consider an even greater confinement by deriving the RET matrix element for a two-dimensional waveguide using ray theory, and compare the resulting RET elements in 3D and 2D and for the 2D waveguide. We see greatly enhanced RET rates over long distances for both the 2D and 2D waveguide systems and see a great preference for transverse photon mediated transfer in the 2D waveguide system. [ABSTRACT FROM AUTHOR]

Radiation-induced property changes in materials originate from the energy transfer from an incoming particle to the existing lattice, displacing atoms. The displaced atoms can cause the formation of extended defects including dislocation loops, voids, or precipitates. The non-equilibrium defects created during damage events determine the extent of these larger defects and are a function of dose rate, material, and temperature. However, these defects are transient and can only be probed indirectly. This work presents direct experimental measurements and evidence of irradiated non-equilibrium vacancy formation, where in situ positron annihilation spectroscopy was used to prove the generation of non-equilibrium defects in silicon. [ABSTRACT FROM AUTHOR]

A decade ago, an electron-attachment process called interatomic Coulombic electron capture has been predicted to be possible through energy transfer to a nearby neighbor. It has been estimated to be competitive with environment-independent photorecombination, but its general relevance has yet to be established. Here, we evaluate the capability of alkali and alkaline earth metal cations to capture a free electron by assistance from a nearby water molecule. We introduce a characteristic distance rIC for this energy transfer mechanism in equivalence to the Förster radius. Our results show that water-assisted electron capture dominates over photorecombination beyond the second hydration shell of each cation for electron energies above a threshold. The assisted capture reaches distances equivalent to a fifth to seventh solvation shell for the studied cations. The far reach of the assisted electron capture is of significant general interest to the broad spectrum of research fields dealing with low-energy electrons, in particular radiation-induced damage of biomolecules. The here introduced distance measure will enable quantification of the role of the environment for assisted electron attachment. [ABSTRACT FROM AUTHOR]

Here, we demonstrate a strategy that two orthogonal modes in a dielectric cavity can efficiently couple with each other through the bridging effect of a plasmonic antenna. In such a dielectric-antenna hybrid system, a plasmonic antenna can coherently interact with both modes of the dielectric cavity, which brings sufficient coherent energy transfers between the two orthogonal modes. Specifically, a broad electromagnetic mode and a narrow whispering gallery mode (WGM) in a subwavelength silicon disk are considered, where they cannot directly interact with each other through near-field couplings. By introducing a plasmonic antenna, coherent energy transfer between the above two modes occurs, which is confirmed by both far-field spectra and near-field distributions. More investigations show that spectral and spatial overlaps between the involved modes can largely affect energy transfer behaviors. Those overlaps are highly dependent on various parameters of the system. The WGM response in the hybrid system can even exceed that of an individual disk. Our proposed strategy can be extended to other similar systems and the modified optical responses can find applications in enhanced light-matter interactions. [ABSTRACT FROM AUTHOR]

Research on lead-free double perovskite has demonstrated its potential as a solution to the stability and toxicity issues associated with lead-based inorganic perovskite white light-emitting diodes (WLED). This current investigation was designed to fabricate, examine, and compare the photoluminescence (PL) characteristics of Cu2+-activated Rb 2 BB'Br 6 (B = K and B′ = Bi) double-perovskite (DP) [A 2 BB'Br 6 ] luminous materials. Bi3+ ions are substituted with Cu2+ ions at their B′ sites. These ions are distributed to the equilibrium valence state and demonstrate minimal variation in ion radius. The microstructure and phase purity of Rb 2 BB'Br 6 :Cu2+ DP were assessed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The Rietveld refinement was also used to identify the crystal structures, and the resulting samples all exhibit cubic crystal structures. The Fm3m space group in Rb 2 BB'Br 6 DP frameworks is significantly impacted by the B sites. The PL spectra were used to thoroughly examine the associated mechanism of the Cu2+ → Bi3+ energy-transfer process. Cu2+ ions can be successfully doped in the Rb 2 KBiBr 6 host with an optical band gap (E g) of 2.74 eV (RKBBr: 0.025Cu2+). The Rb 2 KBiBr 6 :Cu2+ phosphor exhibits distinct emission bands from 450 to 650 nm upon UV excitation at 366 nm. The Cu2+→ Bi3+ energy transfer design allows for systematic luminescence tuning from blue to white due to spectral overlap between the Cu2+ emission and Bi3+ excitation spectra. It has been established that Cu2+ → Bi3+ energy transfer significantly increases the white emission intensity of Bi3+, with an associated colour temperature of 7892 K and an outstanding colour rendering index of 88.8. As a down-conversion luminous material in solid-state illumination for the upcoming generation of display devices, the discovered Rb 2 KBiBr 6 : 0.025Cu2+ phosphor exhibits remarkable promise. [ABSTRACT FROM AUTHOR]

Tm3+ singly- and Dy3+/Tm3+ co-doped CaLaGa 3 O 7 phosphors were prepared successfully by a high-temperature solid-state reaction method and their structure, spectroscopic properties, as well as energy transfer processes between Dy3+ and Tm3+ were studied. The XRD measurements show that all the prepared phosphors have a tetragonal structure. The emission proved that under excitation by 355 nm, 455 nm blue light was obtained in Tm3+: CaLaGa 3 O 7 phosphor with a high color purity (99%). For Dy3+/Tm3+: CaLaGa 3 O 7 , the emission spectra exhibited the typical yellow emissions of Dy3+ and blue light of Tm3+. More importantly, the relative emission intensity of Dy3+ and Tm3+ can be varied by modifying the concentration of Tm3+ and the exciting wavelength, indicating that the luminescence color is tunable. Further, optimal white-light emission was achieved when co-doped 0.01 Tm3+ and 0.02 Dy3+ under 355 nm excitation. Meanwhile, the CIE chromaticity coordinates, color temperature value and color purity of the 0.02 Dy3+/0.01 Tm3+: CaLaGa 3 O 7 phosphor were calculated to be (x = 0.3321, y = 0.3231), 5515 K and 7.18%, respectively, which are close to the standard white-light illumination. Moreover, the study on the decay curves indicates that mutual energy transfers between Dy3+ and Tm3+ take place in the Dy3+/Tm3+: CaLaGa 3 O 7 phosphor. The above findings suggest that the prepared phosphors have potential applications in light emission devices. [ABSTRACT FROM AUTHOR]

The white-light-emitting devices (WLEDs) for urban ecological lighting remain the challenge. The current urban lighting system destroys the growth habits of plants and leads to inhibition of plant growth, reduced branching, smaller leaf area and reduced total dry weight due to excessive blue light. In this work, a series of blue-green and red dual-emission Na 3 Ba 2 Ca(PO 4) 3 :Eu2+, Mn2+ phosphors have been successfully synthesized by the high-temperature solid-state reaction method. The crystal structure, the occupancy of the dopant ions and the luminescence characteristics were carefully investigated. The excitation and emission spectra as well as the decay lifetime confirm the effective energy transfer from Eu2+ to Mn2+, which leads to a tunable luminescence with greatly reduced blue emission. Especially, the optimal Na 3 Ba 2 Ca(PO 4) 3 :0.02Eu2+, 0.11Mn2+ phosphor demonstrates a high internal quantum yield of 99.7%. At 150 °C, the luminescence intensity of Na 3 Ba 2 Ca(PO 4) 3 :0.02Eu2+, 0.11Mn2+ can maintain 64.5% of room temperature intensity. In addition, the WLED device fabricated with Na 3 Ba 2 Ca(PO 4) 3 :Eu2+, Mn2+ phosphor shows white light emission with CIE coordinates of (0.3800, 0.3852), rendering index (Ra) of 65.4 and correlated color temperature (CCT) of 3640 K. These results confirm that the Na 3 Ba 2 Ca(PO 4) 3 :Eu2+, Mn2+ phosphor can be applied as a white light source in the urban ecological field. [Display omitted] • Tunable white Na 3 Ba 2 Ca(PO 4) 3 :Eu2+,Mn2+ were synthesized for the first time. • Occupancy of dopant ions in the matrix is fully analyzed. • The conversion mechanisms are described as cooperative energy transfers from Eu2+ to Mn2+. • The Na 3 Ba 2 Ca(PO 4) 3 :0.02Eu2+,0.11Mn2+ owns high internal quantum yield and urban ecological lighting. • This phosphor can be applied as a white light source in the urban ecological field. [ABSTRACT FROM AUTHOR]

We obtain polynomial bounds on the growth in time of Sobolev norm of solutions to the cubic defocussing nonlinear Schrödinger equation on two dimensional product space. We also give the angular improved bilinear Strichartz estimates for frequency localized functions, which estimates are used for enhancement of a smoothing estimates. Such upper bounds for the growth of Sobolev norms measure the transfer of energy from low to high modes as time grows on. [ABSTRACT FROM AUTHOR]

A series of LaNbO 4 :RE3+ (RE = Tb and Eu) phosphors were successfully synthesized via a calcination-assisted hydrothermal reaction, where the vital roles of solution pH, calcination temperature and NbO 4 3−/La3+ molar ratio in phase/morphology evolution of LaNbO 4 nanocrystals were elaborated. It was unambiguously demonstrated that monoclinic LaNbO 4 can be crystallized at solution pH = 8–13 after calcination at 900 °C. With pH = 10 precursor for example, higher calcination temperature led to phase transformation from orthorhombic to monoclinic structure. LaNbO 4 nanoparticles exhibit self-activated broad-band excitations (1A 1 → 1T 1,2) and emissions (3T 2,1 → 1A 1) within the NbO 4 3− ligand. Intriguingly, Tb3+/Eu3+ incorporations allow for phase tailoring and full-visible-spectrum color-tunable luminescence, where the latter benefits from the effective NbO 4 3− → Tb3+ → Eu3+ energy transfer. LaNbO 4 :0.01 Tb3+,0.01Eu3+ phosphor exhibits stronger white-light emission, which gradually drifts to yellowish green at high heating temperature. This phosphor is an attractive candidate for optical thermometers and warm pc-WLED owning to excellent thermal stability, a low correlated color temperature of ∼5694 K and a high color rendering index of ∼90. [ABSTRACT FROM AUTHOR]

The large size (4 cm × 4 cm × 1 cm) Ce3+-doped high gadolinium oxyfluoride glass with density of 5.83 g/cm³ was prepared by the melt quench method at 1220 °C. The glass is colorless and transparent over the visible range. The prolonged decay time under 275 nm UV light demonstrates the energy transfer from Gd3+ ions to Ce3+ ions. The X-ray excited luminescence spectra (XEL) show the emission peak corresponds to the 5d→4f transitions of Ce3+ ion. The integral emission intensity of glass was compared with that of bismuth germanate oxide (BGO) crystals. The scintillation property of glass was studied under the γ -ray from 137Cs source and a clear energy peak was observed with light yield (LY) over 1100 ph/MeV. The scintillation decay time comprises fast and slow components. All results presented in this work indicate the appropriate potential to be high-energy rays detecting material for CEPC. [ABSTRACT FROM AUTHOR]

The high-temperature solid state reaction approach was used to successfully synthesize novel tunable-color emitting Ca 2 LuTaO 6 phosphors with double perovskite structure that were un-doped, single-doped, and co-doped with Bi3+/Sm3+ ions. The crystal structure, microstructure, steady-state photoluminescence, time-resolved luminescence measurements, and thermal quenching features of the material were studied. The density functional theory method was used to compute the band gap of the Ca 2 LuTaO 6 , and Ca 2 LuTaO 6 : Bi3+, Sm3+ phosphors. The blue emission at 407 nm (with 313 nm excitation) is due to the host's luminescence, while the cyan emission at 480 nm (under 365 nm excitation) is related to the distinctive 3P n − 1S 0 transitions (n = 0, 1, 2) of Bi3+. Similarly, efficient red emission is observed in the case of Sm3+ single-doped Ca 2 LuTaO 6 phosphors. In addition, the Ca 2 LuTaO 6 : 0.04Bi3+, 0.05 S m3+ phosphors exhibit energy transfer phenomena and have excellent thermal stability, the fluorescence intensity at 150 °C maintains 73% of that at 25 °C and has a small chromaticity shift. The intense blue emission at 407 nm was effectively converted to cyan, red, and white light through doping with Bi3+ and Sm3+, and the resulting energy transfer. The results obtained confirm that Ca 2 LuTaO 6 : Bi3+, Sm3+ phosphors as a single matrix have great potential for high-power WLED applications. [ABSTRACT FROM AUTHOR]

A highly efficient and stable green phosphor with a narrow emissionband in a hexagonal aluminate was synthesized based on the energy transfer between Eu2+ and Mn2+ luminescence centers. The related mechanism was elucidated from the viewpoints of the crystal structure and energy level, providing insights for designing novel phosphors with high performance. [ABSTRACT FROM AUTHOR]

The process of Infrared Multiphoton Dissociation (IRMPD) was studied in a mixture of vinyl bromide/chlorodifluoromethane (VBr, C2H3Br/CF2HCl) using single and double infrared pulsed transverse excitations atmospheric CO2 laser beams. The dissociation of VBr was investigated using FTIR, and the product composition was analysed, and various dissociation routes were proposed. The study found that the VBr molecules were more heavily dissociated when exposed to the CF2HCl environment than without it. By using a time-resolved LIF, the kinetics reactions with CF2HCl were explored under pseudo-first-order conditions, and the quenching rate constant for the interaction between CF2HCl and C 2 d 3 Π g was published using the classical Stern–Volmer model. The impact of pulsed laser heating on the generation of C 2 a 3 Π u radicals was also observed. The decrease in the intensity of the C 2 (a 3 Π u) LIF signal was due to faster recombination of the C 2 a 3 Π u radicals, together with a decrease in V - V ′ energy transfer and the pressure oscillations produced by the effect of pulsed laser heating in the irradiated volume and the experimental conditions. [ABSTRACT FROM AUTHOR]

This manuscript presents research on the optoelectronic and energy transfer properties of conjugated polymer poly (N,N′-bis-4-butylphenyl-N,N'-bisphenyl)benzidine (poly-TPD) and laser dye Fluorol 7GA (F7GA) hybrid thin films prepared via solution blending technique. Various weight ratios of F7GA were added to a fixed concentration of poly-TPD to form homogeneous hybrids. The hybrid thin films were characterized using absorption and photoluminescence spectroscopy. The results showed enhanced absorption, widened optical bandgaps, slight blue-shifted emission, and decreased refractive index in the hybrid films compared to pristine poly-TPD. The significant spectral overlap between the emission spectrum of poly-TPD and the absorption spectrum of F7GA, allowing for efficient Förster resonance energy transfer. Parameters including efficiency, distance, lifetime, and probability of energy transfer were calculated to quantitatively analyze energy transfer. Modulation of F7GA content led to tunable emission colors across the visible spectrum. Overall, the successful energy transfer demonstrated in this study paves the way for exciting future directions in the field of poly-TPD/F7GA hybrid materials for advanced optoelectronic applications. [ABSTRACT FROM AUTHOR]

A set of colour tuning K2Ba(MoO4)2: Dy3+/Eu3+ (KBM: Dy3+/Eu3+) phosphors were fabricated by solid-state method. The phase purity of as-prepared materials was validated by XRD and DRS analyses. The KBM: 0.03Dy3+ sample exhibits two major luminescence lines at 481 and 572 nm when excited by 351 nm light, corresponding to Dy3+ ions' typical transitions of 4F9/2 → 6HJ (J = 15/2, 13/2). By introducing Eu3+ ions into KBM: 0.03Dy3+ phosphor, the ET from Dy3+ to Eu3+ ions arises, leading to colour tuning from green via yellowish green to pink with changing Eu3+ ions' concentration, along with the lowest CCT of KBM: 0.03Dy3+/0.03Eu3+ sample. It can be verified by PLE and PL spectra analysis combined with the decay times of KBM: 0.03Dy3+/yEu3+ samples. The energy transfer mechanism is also expounded. Meanwhile, the emission intensities at 423 K still maintain 72.8% for Dy3+ ions and 91.2% for Eu3+ ions relative to 303 K of the KBM: 0.03Dy3+/0.03Eu3+ sample, displaying its brilliant thermal stability. All these results connote that KBM: Dy3+/Eu3+ phosphors are prospected to be used for the near-UV excited white light-emitting diodes. [ABSTRACT FROM AUTHOR]

The investigation of multifunctional bright materials is a popular research topic. The first report of the Bi3+, Tb3+, and Eu3+ triple‐doped garnet‐derived structure Lu2Mg2Al2Si2O12 phosphor is presented in this study. The energy transfer system was constructed with unique ultraviolet (UV) emission of Bi3+ ions, which allows phosphor to be used for temperature sensing with self‐calibration capability, Sa = 0.26% (148 K) and 0.56% (98 K), Sr = 0.15% (98 K), and 0.21% (148 K), indicating a high sensitivity in the low‐temperature region. Tb3+ and Eu3+ ions with better thermal stability under 325 nm excitation were chosen to achieve higher pressure sensing performance, the sensitivity was calculated by fluorescence intensity ratio technique and has maximum sensitivities of up to 0.1887 (SPa) and 0.1621 G/Pa (SPr). This provides a new idea for the ensuing design of brand‐new phosphors for optical pressure sensing. This study provides a new perspective on the versatile applications of phosphors. [ABSTRACT FROM AUTHOR]

Two series of NaY 1-x Tm x GeO 4 olivines with x = 0.005–0.04 and x = 0.0–0.2 have been prepared by the solid state reaction method and citrate technique, respectively. These germanates crystallize in olivine structure and have the orthorhombic lattice, space group Pnma , Z = 4. The diffuse reflectance spectra have been measured and the optical band gap has been estimated. Under 808 nm laser diode excitation, the NaY 1-x Tm x GeO 4 samples yield luminescence in the range of 1300–1600 nm (3H 4 → 3F 4) and 1600–2200 nm (3F 4 → 3H 6). The maximum of luminescence integrated intensity has been achieved for the composition NaY 0·85 Tm 0.15 GeO 4. The luminescence decay kinetics has been explained using migration. The parameters of the cross–relaxation process: 3H 4 + 3H 6 → 3F 4 + 3F 4 were obtained taking into account the energy transfer rate between thulium ions. It is shown that the presented materials are characterized by an effective migration-accelerated cross-relaxation process, which occurs as a result of dipole-dipole interactions. [Display omitted] • The DFT calculations of peculiarities of NaYGeO 4 and NaYGeO 4 :Tm were carried out. • The NaY 1-x Tm x GeO 4 phosphors were synthesized by the solid state reaction method and citrate technique. • Luminescent properties including lifetime were measured in the case of the NaY 0·85 Tm 0.15 GeO 4 germanate, the τ values were found to be 0.014 and 1.55 ms for λ em = 1475 and 1900 nm, respectively. • An energy transfer scheme including migration-accelerated cross-relaxation processes and quantum cutting process was proposed. [ABSTRACT FROM AUTHOR]

The movement of landslide-debris flows is strongly affected by entrainment and runout-path terrain. Herein, mobility alteration was explored from an energy perspective via the discrete element method, using the Shaziba geohazard. The dynamics of the Shaziba geohazard were investigated based on field investigations and numerical simulations. The multiple energy evolutions, conversions, and dissipations of different initiation areas and distinct landslide processes, including kinetic, potential, frictional, and collisional energy, were quantitatively and systematically investigated. The simulation results provide a clear presentation of the inter-particle interactions and energy transfer behavior. Friction caused the most significant energy dissipation, yet collisions dominated the mobility reduction during the entrainment process and interactions with the runout-path terrain. The entrained area possessed higher mobility due to entrainment-induced energy transfer, with distinct forms of energy supplement at different depths. Moreover, the deflection and arching effects of runout-path terrains altered the velocity and direction of landslides and could be used to explain the dissipation of landslide energy as well as reduced mobility. At the cliff, the high-velocity and near-vertical impact on the sediment resulted in the rapid dissipation of landslide energy in collisions. The results provide a reference for analyzing and predicting the movement and mitigating threats of similar geohazards. [ABSTRACT FROM AUTHOR]

Luminescent properties were characterized and investigated in Ca2KMg2V3O12 phosphor. Near infrared (NIR) emission of Nd3+ activator in Ca2KMg2V3O12 host is reported for the first time. NIR emissions around 1μm due to characteristic lanthanide transitions are observed. Excitation spectra reveal that the NIR emission is host-sensitized. The sample was prepared by solution combustion synthesis method. Ca2KMg2V3O12 is a self-activated phosphor belonging to cubic system having space group Ia3̄d with z = 8, a = 12.5 Å. Strong host emission was observed in the blue–green region. It displays broadband emission with an intense band centered at 508nm that spans almost the whole visible light spectrum, from 400nm to 700nm due to the d–d transition of V5+ ions in the (VO4)3− groups. The Ca2KMg2V3O12:Nd3+ phosphor showed NIR emission at 1072nm due to transition 4F3∕2→4I9∕2, for 343nm excitation. Obtained results indicate the significant potential of Ca2KMg2V3O12 phosphor for solid state laser applications. The strong absorption resulting from f–f transitions in the 470–890nm range makes the phosphor appropriate for a number of applications, including solar-pumped lasers. [ABSTRACT FROM AUTHOR]

Optoelectronic implants have gained increasing attention over the last ten years for their clinical applications, such as optogenetics, photodynamic therapy, and deep‐tissue physiological sensing, which are expected to diagnose and treat a large number of diseases, such as Parkinson's and Alzheimer's diseases, visual impairment, and cancer. One of the main challenges for biomedical optoelectronics is to produce a compact, biocompatible system that delivers optical energy into specific tissue regions. While early‐stage devices are initially adopting batteries or wired solutions for energy supply, recent development has shifted toward wireless devices based on alternative methods, such as wireless power transmission, kinetic energy, and photovoltaic harvesting, which do not normally require periodic replacement or servicing and do not constrain the movement of the patient. In this paper, the principles of the main biomedical applications of implantable optoelectronic devices are reviewed. Recent developments in wireless implantable optoelectronic devices are summarized and sorted by their energy transfer mechanisms. These energy transfer techniques are compared in terms of quantitative parameters (electrical power, optical power, operating frequency, size, weight, and operating range), application fields where they are tested, and main advantages and limitations. [ABSTRACT FROM AUTHOR]

Configurationally‐defined dienes are pervasive across the bioactive natural product spectrum, where they typically manifest themselves as sorbic acid‐based fragments. These C5 motifs reflect the biosynthesis algorithms that facilitate their construction. To complement established biosynthetic paradigms, a chemical platform to facilitate the construction of stereochemically defined, functionalizable dienes by light‐enabled isomerization has been devised. Enabled by selective energy transfer catalysis, a variety of substituted β‐boryl sorbic acid derivatives can be isomerized in a regio‐ and stereo‐selective manner (up to 97 : 3). Directionality is guided by a stabilizing nO→pB interaction in the product: this constitutes a formal anti‐hydroboration of the starting alkyne. This operationally simple reaction employs low catalyst loadings (1 mol %) and is complete in 1 h. X‐ray analysis supports the hypothesis that the nO→pB interaction leads to chromophore bifurcation: this provides a structural foundation for selective energy transfer. [ABSTRACT FROM AUTHOR]

The optical and mechanical properties of 2D semiconductors make them excellent candidates for the active components of plastic optoelectronic devices. Here, the integration of single‐layer WSe2 (1L‐WSe2) into a polystyrene (PS) film containing dispersed perylene orange (PDI‐O) molecules is investigated. The findings reveal a notable enhancement in the light emission of 1L‐WSe2, which occurs exclusively upon PDI‐O excitation and scales with the concentration of molecules in the PS film. Moreover, the increase in 1L‐WSe2 photoluminescence coincides with a quenching of the PDI‐O light emission intensity and a decrease in its lifetime. These results point to efficient long‐range interactions, such as Förster energy transfer, between PDI‐O (acting as the donor) and 1L‐WSe2 (acting as the acceptor), as the mechanism responsible for the enhanced light emission in the latter. These findings are of great interest for the development of flexible optoelectronic devices integrating active 2D materials; the polymeric matrix plays a dual role, serving as both physical support and host for organic dopants that can optimize the light emission properties of the active 2D material. [ABSTRACT FROM AUTHOR]

Fast photoluminescence and scintillation with a Stokes shift larger than 1 eV is achieved in hetero‐ligand metal–organic framework (MOF) crystals comprising inorganic linking nodes and fluorescent conjugated ligands. By finely engineering the MOF composition with the use of ligands with strictly complementary emission and absorption properties and highly delocalized molecular electronic orbitals, the singlet excitons diffusion is enhanced through the ligand framework, fully exploiting both Förster and Dexter energy transfer mechanisms. This allows for the sensitization of energy acceptor ligand fluorescence by ultrafast non‐radiative energy transfer with a rate up to the THz range. This efficient antenna effect instantly activates the MOF scintillation with a Stokes shift as large as 1.3 eV in the blue spectral range, matching the highest sensitivity spectral window of the best photodetector available. This is obtained using a minimal doping level of the energy acceptor species, with a consequent elimination of emission re‐absorption that allows the achievement of a 500% increment of the MOFs scintillation efficiency and the detection of the radioactive krypton isotope 85Kr from the gas phase with an improved sensitivity compared with the reference material. [ABSTRACT FROM AUTHOR]

Cyclometalated iridium (Ir) complexes demonstrate impressive capabilities across a range of fields, including biology and photocatalysis, due to their tunable optical characteristics and structure flexibility. However, generating upconversion luminescence of Ir complexes under near‐infrared light excitation is challenging. Herein, by employing lanthanide‐doped upconversion nanoparticles (UCNPs) as the sensitizer, a new strategy is demonstrated to gain upconversion luminescence of Ir complexes via triplet energy transfer. This design relies on a rationally designed hybrid of core‐shell structured NaYbF4:Tb@NaTbF4 UCNPs and new Ir phosphonate complexes, in which UCNPs can migrate upconverted energy to the surface of nanoparticles through Tb3+‐mediated energy migration and then sensitize the upconversion luminescence of Ir complexes upon 980 nm excitation. Both experimental and theoretical investigations highlight the significance of triplet energy transfer from excited Tb3+ ions to the triplet state of Ir complexes in the sensitization of upconversion luminescence of Ir complexes. These findings may open exciting avenues for fabricating hybrid Ir materials with new functions and driving the development of UCNP‐based nanomaterials. [ABSTRACT FROM AUTHOR]