Spectral investigation on single molecular optoelectronics of ladder phenylenes

Spectroscopic study on size-dependent optoelectronics of N-type ultra-high conductive polymer PBFDO

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.

Physical Mechanism of Spectra in Carbon Nanobelts under Quantum Size Effect

Since the successful synthesis of [6,6]carbon nanobelt (CNB), [8,8]CNB and [12,12]CNB have been synthesized successively. CNBs with different sizes ([2N,2N]CNB; N = 2, 3, 4, 5, 6, 7, and 8) have quantum size effects and exhibit completely different optical properties. In this work, the linear and nonlinear optical properties and spectral changes of [2N,2N]CNB are studied based on density functional theory (DFT). The molecular volume, pore volume, and stability of [2N,2N]CNB are investigated. The electron transition mechanism of the one-photon absorption (OPA) and two-photon absorption (TPA) spectra of [2N,2N]CNB is explained, and the extrapolation formula between the wavelength of the absorption peak and the absorption coefficient (ε) and size is given. The infrared (IR) and Raman spectra of [2N,2N]CNB are calculated, and the vibrational modes of characteristic peaks are provided. Finally, the nonlinear optical properties of [2N,2N]CNB are studied, which reflect the anisotropy of molecular polarization. The extrapolation formulas for the polarizability (α) and second hyperpolarizability (γ) of [2N,2N]CNB under different external fields are given. The extrapolation formulas given in this work will help to predict the linear and nonlinear optical properties of arbitrary [2N,2N]CNB beyond computational power, laying the foundation for the practical application of [2N,2N]CNB's theoretical basis.