Molecular aggregates formed by weak interactions between sp-hybridized carbon rings are promising model systems for low-dimensional carbon-based optoelectronic materials. In this work, we theoretically investigated the structural properties, electronic structures, one-photon absorption (OPA), and two-photon absorption (TPA) responses of C₁₈ dimers under external electric fields. Geometry optimizations show that the C₁₈ dimer maintains an intact double-ring framework within the field range of 0.005–0.015 a.u. (a.u.), indicating that the external field mainly modulates the local inter-ring contact rather than disrupting the sp‑carbon skeleton. Weak-interaction and electrostatic-potential analyses were performed to examine the inter-ring contact and local electrostatic environment. The results reveal that the X-direction field mainly induces transverse charge polarization, whereas the Z-direction field compresses the local inter-ring contact at high field strength and enhances local electrostatic-potential redistribution. HOMO–LUMO energy levels and frontier orbital distributions further show that the external field reduces the energy gap and induces field-direction-dependent orbital rearrangement. Excited states were analyzed using OPA/TPA spectra, charge-density differences, transition-density matrices, and transition indices. At 0.015 a.u., the dominant OPA band weakens as its contribution is redistributed from a single state to several closely spaced states. The TPA response is strongly direction dependent: the maximum cross-section increases from 1.85 × 102 Göppert–Mayer (GM) in the field-free C₁₈ dimer to 4.36 × 104 GM in (C₁₈)₂-X0.015, whereas (C₁₈)₂-Z0.015 mainly reconstructs the transition pathways. These results provide molecular-level insight into direction-dependent two-photon modulation in weakly bound sp‑carbon-ring assemblies.

Thermally activated delayed fluorescence (TADF) materials enable nearly 100% internal quantum efficiency in OLEDs, yet the substituent-dependent regulation of excited states in boron-based acceptors remains insufficiently clarified. In this study, we theoretically investigate the blue boron-based TADF emitter BOBT and five of its derivatives (B1-B5) bearing electron-withdrawing groups (-F, -Cl, -CN, -COOH, -COOCH3), to clarify how acceptor engineering influences charge transfer, singlet-triplet separation, and exciton-conversion dynamics. The analysis shows that systematic substitution effectively tunes donor-acceptor decoupling, frontier orbital gaps, ΔE ST, and oscillator strengths. Among the substituted derivatives, B5 presents the most balanced excited-state profile, combining a reduced bandgap, a relatively small ΔE ST of 0.106 eV, and appreciable S1-T1/T2 spin-orbit coupling. These results indicate that targeted acceptor engineering can effectively regulate excited-state energetics and spin mixing in blue TADF materials, although the present calculations do not allow a definitive conclusion that the RISC rate is enhanced relative to the parent molecule B.

Nitrogen reduction reaction (NRR) is necessary as an environmentally friendly and sustainable method for producing NH3 in the context of the energy crisis and increasing environmental concerns. Efficient catalysts play an important role in the NRR reaction. In this work, a high-curvature tetracoordinate transition metal (TM) nitrogen-doped graphene single-atom catalyst was designed and five candidate catalysts with excellent performances were selected from 406 models through a combination of high-throughput screening and density functional theory calculations. Using seven different coordination types MC4, MC3N1, MC2N2-1, MC2N2-2, MC2N2-3, MC1N3 and MN4, of which VN4 (side-on) with four N-atom coordination has the lowest limiting potential of 0.31 V and the competing Hydrogen Evolution Reaction (HER) was suppressed. This work provides guidance for the development of efficient NRR catalysts.

The electronic states of the twist bilayer graphene (TBG) moiré superlattice are usually regulated by the rotation angle, applied electric field, applied magnetic field, carrier concentration and applied stress, and thus exhibit novel physical properties. Squeezing, that is, applying vertical compressive stress to the graphene layers, has profound significance in regulating the photoelectric properties of the moiré superlattice and constructing optical nanodevices. This paper presents the photoelectric properties of a TBG moiré superlattice with a twist angle of 13.17° and tunability under vertical stress. Interlayer distance decreases nonlinearly with compressive stress from 0 to 10 GPa, giving rise to weakened interlayer coupling compared to a Bernal-stacked graphene bilayer and an enhanced repulsive effect between the layers. The calculated Bloch wave functions show a strong dependence on stress. With the increase in stress, the band gaps of the system present a nonlinear increase, which induces and enhances the interlayer charge transfer and leads to the redshift of the absorption spectrum of the moiré superlattice system. By analyzing the differences in the Bloch wave function and charge density differences, we explain the nature of the physical mechanism of photoelectric property change in a stress-regulated twist superlattice system. This study provides a theoretical basis for the identification of piezoelectric properties and the stress regulation of photoelectric devices based on TBG, and also provides a feasible method for regulating the performance of TBG.

Single-molecule plasmas are widely used in spectroscopic studies and plasma devices, and the organic conjugated molecular chain of poly (benzodifurandione) (PBFDO) has excellent electrical conductivity and unique electronic structure. Therefore, an in-depth theoretical study of the spectroscopic, charge transfer and electron transport properties of PBFDO polymers and the analysis of physical mechanisms are essential. In this work, the absorption spectra of neutral and charged PBFDO polymers of different sizes and periodic systems of PBFDO polymers are studied theoretically. The charge transfer modes of the different absorption peaks are also given. The Raman and resonance Raman properties of long-chain PBFDO polymers under 514 nm laser were revealed. The electron transport properties and Current-Voltage Characteristic (I-V) Curves of PBFDO devices were also investigated. This work will provide the necessary theoretical guidance for the application of PBFDO in the field of nanoscale optoelectronics and the design of devices.

In this work, we theoretically investigate the linear and nonlinear optical absorption properties of open triangulene spin chains and cyclic triangulene spin chains in relation to their lengths and shapes. The physical mechanism of local excitation within the triangular alkene unit and the weak charge transfer between the units are discussed. The uniformly distributed electrostatic potential allows the system to have a small permanent dipole moment that blocks the electronic transition in the light excitation such that the electronic transition can only be carried out between adjacent carbon atoms. The one-photon absorption (OPA) spectra and two-photon absorption (TPA) spectra are red-shifted with the addition of triangulene units compared to N = 3TSCs (triangulene spin chains, TSCs). Here, TPA is mainly caused by the first step of the transition. The length of the spin chain has a significant adjustment effect on the photon cross-section. TSCs of different lengths and shapes can control chirality by adjusting the distribution of the electric dipole moment and transition magnetic dipole moment. These analyses reveal the photophysical properties of triangulene and provide a theoretical basis for studying the photophysical properties of triangulene and its derivatives.

Defects, such as twisting, in fused aromatic hydrocarbons disrupt the plane of the π orbital. The twisted structure induces an electric field in the system and affects the spectra. In this work, theoretical studies show that the intramolecular electric field within a distinctly twisted structure is larger than that of other molecules. In addition, the spectral study shows that the degree of charge transfer and the magnetic transition dipole in the electrostatic potential extremum region of the molecular electric field were significantly improved, which affected the optical absorption and chiral optical behavior of the molecule. The discovery of this theoretical regulation law will provide a solid foundation for the electric-field-induced regulation of optical properties and will promote the precise design and synthesis of optoelectronic molecules with inner electric fields.

The one-photon absorption properties (OPA), two-photon absorption properties (TPA), electronic circular dichroism (ECD) spectra and partial DOS (PDOS) of a twist bilayer graphdiyne nanodisk (TwBLGDY-ND) were investigated by using a variety of quantum chemistry and wave function analyses. The physical mechanism of the twist bilayer graphdiyne nanodisk (TwBLGDY) with optical properties regulated by twisting angles was revealed. The results show that the twist angle makes the TwBLGDY form a moiré superlattice structure, and electron excitation mainly occurs in the first ring of the moiré superlattice structure. The contribution of atomic orbitals in these fragments to transition dipole moments is greater and electronic transitions are more likely to occur. When the twist angle increases from 0° to 15°, the absorption spectrum of the system is red shifted, which is mainly due to the enhancement of electron excitation characteristics. When the twist angle increases from 15° to 27.5°, the absorption spectrum of the system is blue shifted, due to the enhanced charge transfer within the layer. On the other hand, the twist angle can regulate the TPA absorption cross section of the system to enhance the intensity of the absorption spectrum. The twist angle can also regulate chirality by adjusting the spatial distribution of electric dipole transition and magnetic dipole transition. This study can provide theoretical guidance for constructing chiral optical devices based on the TwBLGDY structure.

In this work, we theoretically studied the optical absorption properties of a layer-stacked cocrystal heterogeneous material Spe-TCNB cocrystal (STC) which is produced by supramolecular self-assembly of organic conjugated monomers SPE and TCNB. The highly ordered aggregate structure in the cocrystal STC will lead to intermolecular interactions such as π∼π, hydrogen bonds and van der Waals forces, resulting in significant charge transfer characteristics and large cross-sectional two-photon absorption characteristics. The physical mechanism of one-photon and two-photon charge transfer of cocrystal molecules is specifically discussed and the interaction between molecules and their role in charge transfer are quantitatively analyzed. We found that the charge transfer between molecular junctions composed of hydrogen bonds is mainly cross-bridge charge transfer, while the charge transfer between molecular junctions caused by accumulation is mainly cross-space charge transfer. This discovery is of great significance to the design of organic photoelectric functional materials.

Superconducting single crystal of Ca 10 (Pt 4 As 8 )((Fe 0.92 Pt 0.08 ) 2 As 2 ) 5 has been prepared using flux method, and the physical properties of which are careful examined. Resistivity anisotropy between ab plane and c -axis is observed, T −0.5 term originated from the interlayer Josephson coupling is essential to be added to the formula used to describe the out-of-plane resistivity. The density of state (DOS) value at Fermi level derived from the fitting of specific heat data is consistent with the calculation results. Both direct and indirect platinum doping effect have influences on the superconducting transition temperature (T c ) of Ca 10-3(4)-8 system, the T c of our sample falls well into the trend strip formed by the data reported previously.

In this work, based on density functional theory (DFT) and wave function analysis, the properties of absorption spectrum, electronic circular dichroism (ECD) spectrum and Raman spectrum of infinitene (monomer and dimer) with double helical structure are theoretically studied. The electronic excitation properties of infinitene were investigated based on the visualization method charge density difference (CDD) and transition density matrix (TDM). It is found that there is obvious intermolecular charge transfer behavior in the dimer. The electromagnetic interaction mechanism of the chirality of infinitene is explained by decomposing transition electric\magnetic dipole moments (TEDMs\TMDMs). The response of Raman spectra to excitation light of different wavelengths was calculated. Then, the electron delocalization degree and magnetic response intensity of infinitene were studied based on the magnetically induced current under external magnetic field. The interaction of infinitene with the external environment was studied by electrostatic and van der Waals potentials, and it was shown that non-polar or low-polar molecules are more inclined to be adsorbed at the groove position of infinitene. Finally, the mechanism of intermolecular interactions in dimer was investigated based on independent gradient model based on Hirshfeld partition (IMGH), Atoms-In-Molecules (AIM), and energy decomposition analysis based on forcefield (EDA-FF). And revealed that the stacking in the dimer is dominated by dispersive interactions.

The major histocompatibility complex (MHC)I binding affinity models have contributed to screen the candidate peptides, and have assisted the experiments in determining the peptides that can form complexes with MHCImolecules to activate cytotoxic T cells. The transporter associated with antigen processing (TAP) binding models could also be used for screening the candidate peptides. How to make the best of the two types of binding affinity models for screening out the candidate peptides, the similarities and differences between the selectivity of TAP and MHC I molecules in peptides and the biological mechanism of that similarities and differences, these three questions remains obscure. Herein, we rearranged the TAP binding test set, increasing its size to 699. The established TAP binding model based on Kernel-function stabilized matrix method (KSMM) had a higher prediction accuracy than that of the state of the art, achieving a relevant correlation coefficient of 0.89 on a 5-fold cross-validation. The integrative prediction of HLA-A3 affinity and TAP affinity models remarkedly improved the discrimination accuracy, with the AUC value increasing from similar to 0.82 to 0.87. This improvement is due to the different preferences of the two types of affinity models for the best defined amino acids on 2nd and 9th positions, as well as to the complementarity of such different preferences. The results of TAP-peptide docking also supported this conclusion. The TAP model is available online: http://www.bilologymaths.top/mbtwo/major.aspx.