We provide a visualization method to observe the photoinduced charge transfer and electron–hole coherence in the two-photon absorption (TPA), especially including the optical properties in the ...“hidden” intermediate states in TPA. A new method for analyzing the characteristics of two-photon excitation is proposed using a two-step process, which is closest to the physical reality process. These visualization methods include transition density matrix, charge density difference, and transition dipole moment in TPA involving both ground and excited state wavefunctions and the transition dipole moments among electric transitions from ground to intermediate and to final excited states. Our visualization method of photoinduced CT and electron–hole coherence in TPA can promote deeper understanding and design molecules with large cross sections in TPA.
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IJS, KILJ, NUK, PNG, UL, UM
The chiral source and its mechanism in the molecular system are of great significance in many fields. In this work, we proposed visualized methods to investigate the physical mechanism of a chiral ...molecule, where the electric and magnetic interactions are visualized with the transitional electric dipole moment, the transitional magnetic dipole moment, and the transitional electric quadrupole moment, and their tensor product. This will also serve as an effective means of visualizing the interaction of light with matter. The relationship between the molecular Raman optical activity (ROA) response and molecular structure was analyzed in an intuitive way. The relationship between chromophore chirality and molecular vibration mode are revealed via interaction between the transition electric dipole moment and the transition magnetic dipole moment. The molecular chirality is derived from the anisotropy of the molecular transition electric dipole moment and the transition magnetic dipole moment. The anisotropic dipole moment localized molecular chromophore is the source of the vibration mode in which the ROA responds to the reverse.
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IJS, KILJ, NUK, PNG, UL, UM
In this paper, we review the optoelectronic properties and applications of graphene and graphene heterostructures in recent years. Graphene is a 2D crystal with a single atomic layer thickness ...consisting of sp2 hybridized conjugated carbon atoms. Graphene's unique optical and electrical properties have led to its further development in the field of nanoscale optoelectronics. Graphene has extremely high carrier mobility and a wide range of photoelectric response characteristics in conventional semiconductor optoelectronic devices, such as silicon and GaAs. By changing the shape of a graphene structure and combining it with other nanomaterials, nano-optoelectronic devices based on graphene have greatly improved performance. Optoelectronic devices based on graphene have broad application prospects.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Graphene, as a typical two-dimensional nanometer material, has shown its uniqueapplication potential in electrical characteristics, thermal properties, and thermoelectric propertiesby virtue of its ...novel electronic structure. The field of traditional material modification mainlychanges or enhances certain properties of materials by mixing a variety of materials (to form aheterostructure) and doping. For graphene as well, this paper specifically discusses the use oftraditional modification methods to improve graphene’s electrical and thermoelectrical properties.More deeply, since graphene is an atomic-level thin film material, its shape and edge conformation(zigzag boundary and armchair boundary) have a great impact on performance. Therefore, thispaper reviews the graphene modification field in recent years. Through the change in the shape ofgraphene, the change in the boundary structure configuration, the doping of other atoms, and theformation of a heterostructure, the electrical, thermal, and thermoelectric properties of graphenechange, resulting in broader applications in more fields. Through studies of graphene’s electrical,thermal, and thermoelectric properties in recent years, progress has been made not only inexperimental testing, but also in theoretical calculation. These aspects of graphene are reviewed inthis paper.
Aromatic passivators, such as porphyrin, with large π‐backbones have attracted considerable attention to boost the charge carrier in polycrystalline perovskite films, thus enabling the fabrication of ...efficient and stable perovskite solar cells (PSCs). However, they often self‐assemble into supramolecules that probably influence the charge‐transfer process in the perovskite grain boundary. Here, by doping a monoamine Cu porphyrin into perovskite films, two porphyrin‐based self‐assembled supramolecules were successfully prepared between perovskite grains. Crystal structures and theoretical analyses reveal the presence of a stronger interaction between the amine units and the central Cu ions of neighbouring porphyrins in one of the supramolecules. This has a modified effect on the dipole direction of the porphyrins to be quantized as homogeneously large polarons (HLPs) in a periodic lattice. The porphyrin supramolecules can stabilize perovskite grain boundaries to greatly improve the stability of PSCs, while the HLPs‐featured supramolecule facilitates hole transport across perovskite grains to remarkably increase the cell performance to as high as 24.2 %. This work proves that the modulation of the intermolecular interaction of aromatic passivators to yield HLPs is crucial for the cascaded acceleration of charge transport between perovskite grains.
Charge transport behavior of two amine Cu porphyrin supramolecules with different stacking interactions in perovskite grain boundaries was investigated in detail. Results prove that the construction of homogeneously large polarons (HLPs) in aromatic passivators is a key factor for the charge transport between perovskite grains. This work also affords a new strategy to design new optoelectronic materials with improved charge mobilities.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this work, the relationship between multiple solvent parameters and charge transfer index was analyzed by multi-factor multi-variate partial least squares regression (PLSR). The charge transfer of ...the molecule is visualized by the analysis of the excited state wave function. Hydrogen bond basicity and surface tension can significantly affect charge transfer by studying the solvation model parameters and charge transfer index. Finally, a method in which a solvent regulates charge transfer strength and migration length is proposed.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In this paper, we theoretically analyze the nature of chirality induced by molecular self-assembly with molecular dynamics and visualization methods. Firstly, the dynamics of molecular self-assembly ...of biphenylenes system are demonstrated in detail. Secondly, the molecular interactions for the assembled molecules are analyzed with the weak intermolecular forces. Thirdly, electron-hole coherence and charge transfer in optical absorption are demonstrated with a transition density matrix and charge difference density, respectively. The detailed visualized analysis of electric and magnetic transition dipole moment integrals reveals the nature of chirality of assembled molecules in electronic circular dichroism (ECD) spectroscopy. The Raman optical activity (ROA) spectra demonstrate that the chirality of assembled molecules is strongly dependent on the pre-resonance Raman spectra, based on the optical absorption and ECD spectroscopy. Our visualized analysis method can well reveal the nature and origin of chirality of molecular self-assembly.
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•Firstly, the dynamics of molecular self-assembly of biphenylenes system are demonstrated in detail.•Secondly, the molecular interactions for the assembled molecules are analyzed with the weak intermolecular forces.•Thirdly, electron-hole coherence and charge transfer in optical absorption are demonstrated with a transition density matrix and charge difference density, respectively.•The detailed visualized analysis of electric and magnetic transition dipole moment integrals reveals the nature of chirality of assembled molecules in ECD spectroscopy.•The ROA spectra demonstrate that the chirality of assembled molecules is strongly dependent on the pre-resonance Raman spectra.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The two-dimensional nanomaterials graphene and hexagonal boron nitride (h-BN) have good thermal properties. When the two are combined together to form a planar C-BN hybrid structure or a van der ...Waals heterostructure due to the differences in crystal lattice and the electronic structure between graphene and h-BN, the new material is formed with novel thermal characteristics. We focus on the thermal properties of the two new materials as they change their configuration, size, and number of layers and review these novel characteristics.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The Coherent anti-Stokes Raman scattering (CARS) microscopy is employed to characterize porous carbon materials. The slices of two dimensional (2D) CARS images are obtained, using Z-scan technology. ...Furthermore, the three dimensional (3D) image of CARS is reconstructed with the Z-scanned 2D CARS images. The visualizations of rotation for 3D CARS are also shown. The 2D and 3D CARS images with rotations can clearly characterize the structures and properties of porous carbon materials, including the surface and inner parts. Nonlinear optical second harmonic generation demonstrates the inversion symmetry breaking of porous carbon materials, which is not centrosymmetric material. The two-photon excitation fluorescence image reveals that porous carbon material is of weak auto-fluorescence. The clearly observed signal of two photon-excitation fluorescence provides direct evidence that photon momentum transfer to the electron system occurs. Experimental results demonstrate that the nonlinear optical microscopy is a great optical analysis method for the study of porous carbon materials, and can be potentially used for the optical characterization on the materials at micro-nano-scale.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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