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Developing new organic radical emission systems and regulating their luminescence properties presents a significant challenge. Herein, we build dynamic and multi-emission band radical luminescence systems by co-assembling inorganic metal salts with carbonyl compounds in ionic liquids. After the assembling, dual-band, and excitation wavelength-dependent emission was observed upon ultraviolet light irradiation, one emission band originates from carbonyl radical after light irradiation, the other band from the ligand-metal charge transfer (LMCT) state, which benefits from the charge transfer from the radicals to the metal salts. The dual emission centers also introduce excitation wavelength-dependent properties for the molecules. In addition, three-band emission covering the visible and near-infrared regions can be shown when two or three kinds of metal ions are simultaneously doped into the radical system driven by the ligand-metal-metal charge transfer (LMMCT). Interestingly, visible light can quickly quench the radical emission of systems, thus realizing a dynamic luminescence. The LMMCT effect and strong supramolecular interactions significantly improve the photoluminescence quantum yield by up to 67.2 %. Moreover, such materials can be successfully used for detecting radioactive metal ions and information encryption. This study develops a platform for manufacturing various metal-organic radical emission systems with diverse properties.

Complex donor arms in thermally-activated delay fluorescence (TADF) molecules can potentially provide additional options for charge-transfer (CT) emission through higher twisting disorder, leading to broader emission spectra. Here we design novel TADF emitters with double twisted donor moieties and show that a structural complication of the carbazole-based donor arms by changing the molecular structure from D-A-D to D2-D1-A-D1-D2 yields a transition from a dual to a triple emission band with an additional CT emission component, providing a corresponding red shift and increasing low-energy emission contribution. The revealed relationship between increased complexity of the donor moiety and the multicomponent CT emission band in the D-A-D structures provides a clue for design of TADF emitters with extended emission spectra.

The line list is essential for accurately modeling various astrophysical phenomena, such as stellar photospheres and atmospheres of extrasolar planets. This paper introduces a new line database for the PS molecule spanning from the ultraviolet to the infrared regions, covering wavenumbers up to 45000 cm- ¹ and containing over ten million transitions between 150,458 states with total angular momentum J < 160. Accurate line intensities for rotational, vibrational and electronic transitions are generated by using the general purpose variational code DUO. Before applying the DUO program, the potential energy curves (PECs), the electric dipole transition moments (EDTMs) and the spin-orbit coupling (SOC) matrix need to be provided, which are computed by an ab initio method at the icMRCI level. The DUO program is executed to generate two files- a state file and a transition file, which are provided to the ExoCross program which supply cross sections, intensities, partition functions, lifetimes and quantum number assignments. The cross-sections and intensities for the observed transitions are necessary for the correct modeling of the spectra. Tests of the line lists show that our predictions not only provide a favorable comparison with the experimental spectrum but also a cornerstone for various astronomical observations.

The oxidative degradation of plastics in conjunction with the production of clean hydrogen (H₂) represents a significant challenge. Herein, a Ni₃S₄/ZnCdS heterojunction is rationally synthesized and employed for the efficient production of H₂ and high-selectivity value-added chemicals from waste plastic. By integrating spectroscopic analysis techniques with density functional theory (DFT) calculations, a solely electron transfer-mediated reaction mechanism is confirmed, wherein Ni₃S₄ extracts electrons from ZnCdS (ZCS) to promote the spatial segregation of photogenerated electrons and holes, which not only facilitates H₂ production but also maintains the high oxidation potential of holes on the ZCS surface, favoring hole-dominated plastic oxidation. Notably, the catalyst exhibited efficient H₂ production rates as high as 27.9 and 17.4 mmol g^-1 h^-1, along with a selectivity of 94.2% and 78.3% in the liquid product toward pyruvate and acetate production from polylactic acid (PLA) and polyethylene terephthalate (PET), respectively. Additionally, carbon yields of 26.5% for pyruvate and 2.2% for acetate are measured after 9 h of photoreforming, representing the highest values reported to date. Overall, this research presents a promising approach for converting plastic waste into H₂ fuel and high-selectivity valuable chemical products, offering a potential solution to the growing issue of "White Pollution".

We have measured the core-valence double ionization spectra of carbon suboxide above both the O 1s and C 1s edges. Following several core-valence cases known in the literature, to begin with the spectra are compared with the well-known single ionization valence photoelectron spectrum of this system, from which they surprisingly differ quite strongly. This motivates a comparison to electronic structure calculations carried out within the sudden approximation where the overlap between the core and valence orbital is included, while still assuming decoupling of the core and valence ionization events. The substantially improved agreement indicates that this more complex description is needed to model the core-valence double ionization process adequately in the present case. Accordingly, assignments of spectral features are made by comparison of our experimental and numerical spectra. Auger decay following C 1s hole formation at the chemically distinct central and outer C atoms shows strong selectivity in the final multiply charged states produced, for initial core-valence ionization, being consistent with the Auger decay from single core ionization. Comparison to calculations allows for the identification of the initial core ionization site for the Auger decay following core-valence ionization.

Organic hole-transporting materials (HTMs) with high hole mobility and a defect passivating ability are critical for improving the performance and stability of perovskite optoelectronics, including perovskite quantum dot light-emitting diodes (Pe-QLEDs) and perovskite solar cells. In this study, we designed two small-molecule HTMs, termed X13 and X15, incorporating the methylthio group (SMe) as defect-passivating sites to enhance the interaction between HTMs and the perovskite layer for Pe-QLED applications. Our study highlights that X15, featuring SMe groups at the para-position of the carbazole unit, demonstrates a strong interaction and superior passivation effects with perovskite quantum dots. Consequently, Pe-QLEDs (0.09 cm²) incorporating X15 as the HTM achieve a maximum external quantum efficiency (EQE) of 22.89%. Moreover, employing X15 in large-area Pe-QLEDs (1 cm²) yields an EQE of 21.10% with uniform light emission, surpassing the PTAA-based devices (EQE ∼ 15.03%). Our finding provides crucial insights into the molecular design of defect-passivating small-molecule HTMs for perovskite light-emitting diodes and related optoelectronic devices.

Nitrogen substitutions have shown a great impact for the development of thermally activated delayed fluorescence (TADF)-based organic light-emitting diode (OLED) materials. In particular, much focus has been devoted to nitrogen-substituted polycyclic aromatic hydrocarbons (PAHs) for TADF emitters. In this context, we provide here a molecular design approach for symmetric nitrogen substitutions in fused benzene ring PAHs based on the dibenzo[a,c]picene (DBP) molecule. We designed possible donor–acceptor (D–A) compounds with dimethylcarbazole (DMCz) and dimethyldiphenylamine (DMDPA) donors and studied the structure and photophysics of the designed D–A compounds. The twisted and extended D–A-type PAH emitters demonstrate red and near-infrared (NIR) TADF emission. Nitrogen substitutions lead to significant LUMO stabilization and reduced HOMO–LUMO energy gaps as well. Additionally, we computed significantly smaller singlet–triplet energy splittings (ΔE_ST) in comparison to non-nitrogen-substituted compounds. The investigated ortho-linked D–A compounds show relatively large donor–acceptor twisting separation and small ΔE_ST compared to their para-linked counterparts. For higher number nitrogen (4N)-substituted emitters, we predict small adiabatic ΔE_ST (ΔE_ST^adia) in the range 0.01–0.13 eV, and with the tert-butylated donors, we even obtained ΔE_ST^adia values as small as 0.007 eV. Computed spin–orbit coupling (SOC) for the T₁ triplet state on the order of 0.12–2.28 cm^–1 suggests significant repopulation of singlet charge transfer (¹CT) excitons from the triplet CT and locally excited (³CT+LE) states. Importantly, the small ΔE_ST^adia and large SOC values induce a reverse intersystem crossing (RISC) rate as high as 1 × 10⁶ s^–1, which will cause red and NIR delayed fluorescence in the 4N-substituted D–A emitters. Notably, we predict red TADF emission for the para-linked compound B4 at 670 nm and the ortho-linked compound D4 at 713 nm and delayed NIR emission at 987 and 1217 nm for the ortho-linked compounds D3 and E3, respectively.

Oxidative dimerization of π-conjugated molecules is a straightforward approach for effectively extending π-conjugation and absorption features. However, it is challenging to construct dimeric species of bulky π-conjugated frameworks because of the steric hindrances and/or poor regioselectivity. To address these issues, a pyrrole unit has been regioselectively appended to the α position of N-confused hexaphyrin (1.1.1.1.1.0) 1 by a facile acid-catalyzed condensation reaction, leading to the formation of pyrrole-appendant 2. Subsequent oxidation of 2 yielded an inner-fused monomer 2F and two fused dimeric species, namely, (2F)₂a and (2F)₂b. In contrast, oxidation of the corresponding Ni(II) complex 2Ni generated dimer (2Ni)₂. Subsequent demetalation resulted in the formation of bipyrrole-linked freebase dimer (2)₂, which could chelate Ni(II) and Cu(II) ions to furnish complexes (2Ni)₂ and (2Cu)₂, respectively. In comparison to the fused dimeric species (2F)₂a and (2F)₂b, the nonfused dimer (2)₂ and its complexes (2Ni)₂ and (2Cu)₂ exhibit diminished local aromaticity, narrowed HOMO–LUMO gaps, and a red-shifted absorption profile that extends up to 2200 nm. These findings underscore a potent strategy for creating expanded porphyrin dimers, wherein the aromaticity and near-infrared absorption can be fine-tuned by incorporating an appendant pyrrole unit

Carbon dots (CDs) are cutting-edge nanomaterials that hold considerable promise in fields such as bioimaging, optoelectronics, and sensing owing to their distinctive optical characteristics and compatibility with biological systems. Nevertheless, the restricted range of multicolor emissions and the intricate methods required for the synthesis have hindered their wider application. Herein, quinoline quaternary ammonium salts are selected as precursors because of their tunable photoluminescence by charge distribution, conjugate effects, and chemical environments, which are expected to be retained in the CDs. This solves the above problems by presenting dual-emission CDs (DE-CDs) that offer finely adjustable emissions ranging from blue to red fluorescence achieved through straightforward synthesis methods. The two emission bands from core and surface states display sensitivity toward excitation wavelength, concentrations, and solvents. These excellent characteristics enable precise ratiometric sensing for water detection and facilitate multicolor luminescent applications. Notably, DE-CDs retain their unique optical properties in PMMA composites, indicating potential applications in multicolor and solid-state luminous technologies. The insights gained from this work not only contribute to the fundamental understanding of CD luminescence but also lay the groundwork for creating advanced optical devices that feature tunable emission characteristics.

Spectroscopic properties of the Se₂⁺ cation are studied using high-level ab initio methods. Scalar relativistic (SR) corrections, core-valence (CV) electron correlation and spin-orbit coupling (SOC) effects are taken into account. The potential energy curves (PECs) of 19 Λ-S states and 52 Ω states generated from the Λ-S coupling scheme are obtained at the multireference configuration interaction plus Davidson correction (MRCI + Q) level of theory. The spectroscopic constants of bound states have been calculated, showing good agreement with previous experimental Se₂ photoionization results. Various curve crossings involving the b⁴Σ^-_g and B²Σ^-_g states of Se⁺₂ are revealed and their predissociation mechanisms are predicted. Finally, the electric dipole transition moments and Franck-Condon factors of the b⁴Σ^-_g - a⁴Π_u, B²Σ^-_g - A²Π_u, C²Σ⁺_u - X²Π_g, and A²Π_u -X²Π_g transitions are obtained and augmented by estimations of the radiative lifetimes of the photo-stable excited b⁴Σ^-_g, B²Σ^-_g, C²∑^-_u, and A²Π_u states. We believe that our research can provide a basis for further experimental studies of the Se₂⁺ cation including predictions of its luminescence which also may be of astrophysical interest since selenium already has been detected in space.