Theoretical investigations on electronic structures and photophysical properties of novel bridged triphenylamine derivatives (original) (raw)
Related papers
Optoelectronic properties of novel alkyl-substituted Triphenylamine derivatives
Organic Electronics, 2017
Hole transport characteristics in three new organic compounds based on triphenylamine (TPA) moiety are presented. The effect on electrical and optical properties of TPA, attached with methyl or tert-butyl side groups, has been investigated through measurement of current density versus voltage (J-V), capacitance versus voltage (C-V), frequency dependent capacitance, acconductivity, Impedance spectroscopy, UV-Vis spectroscopy, Photoluminescence (PL) spectroscopy and X-Ray Diffraction (XRD) studies. These measurements reveal that, the attachment of methyl or tert-butyl group in the para-position of the TPA moiety leads to improved optoelectronic properties and greater molecular stability. XRD analysis of the samples indicates that the inter-molecular distance is the lowest for TPA with tert-butyl side group (3.43
Novel hole transporting materials based on 4-(9H-carbazol-9-yl)triphenylamine derivatives for OLEDs
Molecules (Basel, Switzerland), 2014
During the past few years, organic light emitting diodes (OLEDs) have been increasingly studied due to their emerging applicability. However, some of the properties of existing OLEDs could be improved, such as their overall efficiency and durability; these aspects have been addressed in the current study. A series of novel hole-transporting materials (HTMs) 3a-c based on 4-(9H-carbazol-9-yl)triphenylamine conjugated with different carbazole or triphenylamine derivatives have been readily synthesized by Suzuki coupling reactions. The resulting compounds showed good thermal stabilities with high glass transition temperatures between 148 and 165 °C. The introduction of HTMs 3b and 3c into the standard devices ITO/HATCN/NPB/HTMs 3 (indium tin oxide/dipyrazino(2,3-f:2',3'-h)quinoxaline…
Zeitschrift für Physikalische Chemie, 2017
Geometrical parameters, electronic structures and photophysical properties of three new triphenylamine (TPA) and diphenylamine (DPA) based electron donor materials M1 M3 (for organic solar cells) have been investigated through density functional theory (DFT) methods at the B3LYP/6-31G(d) level of the theory. TPA and DPA are used as donor moieties due to their electron donating ability while benzothiazole, cyanide and cyanomethylacetate (CMA) moieties have been taken as acceptor moieties. The time dependent-DFT (TD-DFT) method has been employed [TD-B3LYP/6-31G (d)] for the computation of excited state properties in the gas phase and in solvent (chloroform). The polarization continuum model is applied for calculations in the solvent phase. The designed molecules exhibited broad absorption in the visible and near infra-red region of spectrum with respect to a reference molecule “R” of a similar class of compounds. Based on reorganization energies calculations, these materials could act...
Solar Energy Materials and Solar Cells, 2011
A series of new ''D-A-D'' chromophores containing hexafluorocyclopentene thiophene as an acceptor and a triphenylamine unit as a donor, called TP-G1, TP-G2, TPB-G1 and TPB-G2, were designed and synthesized. Heterojunction organic photovoltaic (OPV) cells containing these chromophores were fabricated, and device 1, with the structure of ITO/PEDOT:PSS/TP-G1:P3HT/LiF/Al, displayed an opencircuit voltage (V oc ), short-circuit current (J sc ) and power-conversion efficiency (Z) of 0.74 V, 1.178 mA/cm 2 and 0.22%, respectively. The triphenylamine group could effectively induce the open-ring isomer to close because the 4-and 4 0 -positions of the benzene rings were substituted by an electron-donating group and the value of the quantum yields of the closed-ring isomers increased. As a result, the closed-ring isomer facilitated intramolecular p-electron delocalization and exhibited a broad absorption band ranging from 200 to 850 nm. Due to the fluorine substitution of hexafluorocylopentene at the molecular center and the hole-transport characteristics of the triphenylamine moiety on the periphery, our chromophores showed obvious dual semiconductor properties, i.e., n-and p-type, which demonstrated a potential application for OPV devices.
2019
In this work, we studied the effect of different substituents on the electronic and optical properties of six new triphenylamine derivatives using quantum chemistry methods such as DFT and TD-DFT. These calculations were undertaken by the B3LYP exchange and correlation hybrid functional and the 6-31G(d,p) basis set. This model allowed us to determine the optimized structures and electronic and optical properties (EHOMO, ELUMO, Egap, λabs,Voc, ...) of various compounds studied. We also simulated the UV-visible spectrum using the TD-DFT with different functionals by introducing the solvent effect (THF). The TD-CAM-B3LYP and WB97XD methods were found to be the most effective as they have given results that are more consistent with experience. The study shows that modifying the molecule skeleton can greatly improve the performance of the molecule. It also reveals that all of the studied compounds are promising candidates for an effective organic solar cell, especially the M6 which has s...
ChemPhysChem, 2008
Herein, we describe the molecular electronic structure, optical, and charge‐transport properties of anthracene derivatives computationally using density functional theory to understand the factors responsible for the improved efficiency and stability of organic light‐emitting diodes (OLEDs) with triphenylamine (TPA)‐substituted anthracene derivatives. The high performance of OLEDs with TPA‐substituted anthracene is revealed to derive from three original features in comparison with aryl‐substituted anthracene derivatives: 1) the HOMO and LUMO are localized separately on TPA and anthracene moieties, respectively, which leads to better stability of the OLEDs due to the more stable cation of TPA under a hole majority‐carrier environment; 2) the more balanceable hole and electron transport together with the easier hole injection leads to a larger rate of hole–electron recombination, which corresponds to the higher electroluminescence efficiency; and 3) the increasing reorganization energ...
Journal of Materials Chemistry, 2006
This work describes bipolar 2,5-diaryl-1,3,4-oxadiazole-fluorene hybrids which incorporate triphenylamine or carbazole units within the p-electron system, viz. compounds 7, 8, 14 and 16. A related bipolar bis(oxadiazolyl)pyridine system 20 is reported. The syntheses of these five new materials are discussed, along with their optoelectronic absorption and emission properties, and their solution electrochemical redox properties. Anodic electropolymerisation of 20 was observed. Calculations using DFT (density functional theory) establish that they all possess a significantly higher HOMO energy level (by 0.60-1.02 eV) than 1,3-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl]benzene (OXD-7) due to the presence of electron-rich amine moieties and increased conjugation lengths, thereby leading to more balanced charge-transport characteristics. Devices were fabricated by spin-coating techniques using the bipolar compounds as the emitters in the simple device architecture ITO:PEDOT-PSS:X:Ca/Al (X = 7, 8, 14, 16 or 20). The turn-on voltages were 2.9, 5.5, 3.6, 4.5 and 3.4 V for the devices incorporating 7, 8, 14, 16 and 20, respectively. The highest external quantum efficiency (EQE) was observed for compound 7: viz. EQE 0.36%; current efficiency 1.00 cd A 21 ; power efficiency 0.56 lm W 21 at 5.7 V. The EQE of the device fabricated from 8 was considerably lower than for devices using other materials due to low light emission. The EL emission peaked at l max 430, 487, 487 and 521 nm for 8, 14 and 16, and 7, respectively. For the 20 device l max = 521 nm and 564 nm. Thus the HOMO-LUMO gap has been modified, allowing the colour of the emitted light to vary from light blue through to green by the systematic chemical modification of the molecular subunits. The high chemical and thermal durability of these materials combined with the simplicity of the device structure and low turn-on voltages offers considerable potential for OLED applications. { Electronic supplementary information (ESI) available: Synthesis of 11; cyclic voltammetry data for compounds 7, 8, 14, 16 and 20, X-ray crystallographic data for compounds 11, 12, 13 and 20 including diagrams and discussion of the structures; B3LYP/6-31G(d) optimised geometries ; orbital energy level diagrams and frontier orbital localisation for compounds 7a, 8a, 14a, 16a and 20; EL spectra of blended layer devices of MEH-PPV and compound 7. See