Theoretical Study of Optical and Electronic Properties of Unsymmetrical Dendritic Molecules with Different Bridge Moieties

2011 ◽  
Vol 64 (11) ◽  
pp. 1475 ◽  
Author(s):  
Yanling Wang ◽  
Qiang Peng ◽  
Ying Liang ◽  
Benlin Li ◽  
Weiguo Zhu

Molecules bearing polyphenylphenyl dendrons show great potential for applications in organic light-emitting diodes. In this paper, quantum-chemical calculations have been applied to investigate the structural and electronic properties of typical molecules bearing polyphenylphenyl dendrons, 2-(2′,3′,4′,5′-tetraphenyl)phenyl-5-(p-N,N-dimethyl)phenyl pyridine (A), 1-(2′,3′,4′,5′-tetraphenyl)phenyl-4-(p-N,N-dimethyl)phenyl benzene (B), 2-(2′,3′,4′,5′-tetraphenyl)phenyl-5-(p-N,N-dimethyl)phenyl thiophene (C), 1-(2′,3′,4′,5′-tetraphenyl)phenyl-2,5-dimethoxy-4-(p-N,N-dimethyl)phenyl benzene (D), and 2-(2′,3′,4′,5′-tetraphenyl)phenyl-5-(p-N,N-dimethyl)phenyl furan (E). The geometrical and electronic structures in the ground state and lowest singlet excited states have been optimized by B3LYP/6-31G(d) and TD-B3LYP/6-31G(d) methods, respectively. The important parameters, including ionization potential (IP), electron affinity, the reorganization energies (λ), hole extraction potential, and electron extraction potential, first lowest singlet excitation energies, maximum absorption and emission wavelengths are also systematically investigated. The result implied that the HOMO, energy gaps, and IP are affected by the central aromatic ring in the order of phenylene>pyrryl> 2,5-dimethoxyphenylene>thienyl>furyl. The solvent effects on absorption and emission spectra were further examined using the polarizable continuum model.

2011 ◽  
Vol 7 ◽  
pp. 432-441 ◽  
Author(s):  
Scott Fleming ◽  
Andrew Mills ◽  
Tell Tuttle

In the current work we have investigated the ability of time-dependent density functional theory (TD-DFT) to predict the absorption spectra of a series of oxazine dyes and the effect of solvent on the accuracy of these predictions. Based on the results of this study, it is clear that for the series of oxazine dyes an accurate prediction of the excitation energy requires the inclusion of solvent. Implicit solvent included via a polarizable continuum approach was found to be sufficient in reproducing the excitation energies accurately in the majority of cases. Moreover, we found that the SMD solvent model, which is dependent on the full electron density of the solute without partitioning into partial charges, gave more reliable results for our systems relative to the conductor-like polarizable continuum model (CPCM), as implemented in Gaussian 09. In all cases the inclusion of solvent reduces the error in the predicted excitation energy to <0.3 eV and in the majority of cases to <0.1 eV.


2011 ◽  
Vol 503 (1-3) ◽  
pp. 75-79 ◽  
Author(s):  
Xiaojun Liu ◽  
Dan Yang ◽  
Haidong Ju ◽  
Feng Teng ◽  
Yanbing Hou ◽  
...  

2015 ◽  
Vol 39 (5) ◽  
pp. 4147-4153 ◽  
Author(s):  
Yanling Si ◽  
Shuai Zhang ◽  
Nan Qu ◽  
Guoyou Luan ◽  
Zhijian Wu

The influence of the ancillary ligands for iridium complexes on the electronic structures, absorption and emission spectra, and quantum efficiency was investigated. The results reveal that they not only tune the energy gap but also enhance the quantum efficiency.


2021 ◽  
Vol 2063 (1) ◽  
pp. 012002
Author(s):  
Dalal H Alsawad ◽  
Ali A Al-Riyahee ◽  
Ali J Hameed

Abstract A series of 4-(para-substituted phenyl)-1,2,3-selenadiazole adducts of [VO(acac)2] were studied by density functional theory (DFT) calculations. The 4-(para-substituted phenyl)-1,2,3-selenadiazole molecules have been selected to be bound with vanadium atom in [VO(acac)2] through Se, N2 and N3. The resulting adducts have been investigated in two geometries (cis and trans) in order to show the effect of such structural change on the electronic properties of the studied adducts. The optimized geometries, (binding and reorganization) energies and the spatial distribution of the highest molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the adducts are presented and discussed.


2014 ◽  
Vol 904 ◽  
pp. 195-199
Author(s):  
Yuan Fang Hu ◽  
Guang Hua Nie

N-Hexyl-4-(thiophen-2-yl)-1,8-naphthalimide (HTNI) is one of the 1,8-naphthalimide derivatives with excellent fluorescence property. A scheme of time-dependent density functional theory (TDDFT) and configuration interaction singles (CIS) approach in conjunction with polarizable continuum models (PCMs) are employed to make a detailed investigation of the emitting energy. The transition energies of absorption and emission are computed using five exchange-correlation (XC) functionals, B3LYP, PBE0, M06, CAM-B3LYP, and wB97XD as well as 6-31G* and 6-31+G* basis sets. The results show that the predicted emitting energies as well as the absorption ones are dominated mainly by XC functional to be used. By comparing the calculated electron transition energies to experimental observations, it is found that PBE0 functional in combination with 6-31G* basis set is the best method to reproduce the experimental spectra of HTNI.


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