Synthesis, thermal, electrochemical, and photophysical characterization of 1,5-bis(diarylamino)naphthalene derivatives as potential hole transport OLED materials

2005 ◽  
Vol 83 (6-7) ◽  
pp. 958-968 ◽  
Author(s):  
Jingning Shan ◽  
Glenn PA Yap ◽  
Darrin S Richeson
Keyword(s):  
Photophysical Properties ◽  
Energy Levels ◽  
Hole Transport ◽  
Similar Degree ◽  
Naphthalene Derivatives ◽  
Emission Data ◽  
Oxidation Potentials ◽  
Hole Transporting ◽  
Palladium Catalyzed ◽  
The Difference

Novel 1,5-bis(diarylamino)naphthalene derivatives (1–9), which have potential as hole-transporting materials for electroluminescent devices, were obtained through palladium-catalyzed coupling of diarylamines and 1,5-dibromonaphthalene. The thermal, electrochemical, and photophysical properties of these compounds were examined and the effects of the N-aryl substituents on these properties were investigated. These materials possess glass transition temperatures (Tg) that range from 70–131 °C and these values are related to the identity of the aryl substituents. Cyclic voltammetric measurements demonstrated that these compounds possess two reversible oxidation processes and were further used to estimate the HOMO energy levels of these materials by comparison with the ferrocene/ferrocenium couple. The intramolecular charge mobility, as gauged by the difference between the two oxidation potentials, indicates that compounds 1–8 have a similar degree of delocalization as meta-diaminobenzene derivatives while that of 9 is similar to TPD. Compounds 1–9 emit in the blue-green region and optical absorption and emission data for these materials can be rationalized in terms of the electronic donating properties of the aryl substituents. This data when combined with the electrochemically determined HOMO energies allowed estimation of the LUMO energy levels.Key words: hole transport materials, diaminonaphthalene, thermal analysis, palladium-catalyzed arylation.

Investigation of Organic-Organic Interfaces by Time-Resolved Photocurrent, Electrochemical, And Photoemission Techniques

1997 ◽  
Vol 488 ◽  
Author(s):  
Liang-Bih Lin ◽  
M. Gary Mason ◽  
Ralph H. Young ◽  
Deniz E. Schildkraut ◽  
Paul M. Borsenberger ◽  
...  
Keyword(s):  
Hole Transport ◽  
Hole Injection ◽  
Photoemission Spectroscopy ◽  
Energy Barriers ◽  
Time Resolved ◽  
Transient Photocurrent ◽  
Oxidation Potentials ◽  
Organic Interfaces ◽  
Hole Transporting ◽  
Organic Electroluminescent

AbstractHole transporting properties and energy barriers at organic-organic interfaces relevant to electrophotographic and organic electroluminescent (EL) devices are described. Three wellknown hole transporting molecules, 1,1-bis(di-4-tolylaminophenyl)cyclohexane (TAPC), N,N′- diphenyl-N,N′-bis(1 -naphthyl)-(1,1 ′-biphenyl)-4,4′-diamine (NPB), and N,N,N′,N′-tetrakis(4- tolyl)-(1,1 ′-biphenyl)-4,4′-diamine (TTB) are used in this study. The ionization potentials (IP) and oxidation potentials (Eox) of these materials are determined by photoemission spectroscopy and electrochemical measurements, from which a conversion formula is obtained (IP ∼ 4.5 eV + eEox). Hole transport across organic-organic interfaces is investigated by time-of-flight transient photocurrent techniques. The efficiencies of hole injection are consistent with the energy barriers, when present, at these interfaces.

Both Luminous Efficiency and Lifetime Enhancement in Blue Fluorescence OLEDs by Modifying Molecular Structure of Hole Transporting Material

2011 ◽  
Vol 1286 ◽  
Author(s):  
Yoonhyun Kwak ◽  
Sun-Young Lee ◽  
Hye-In Jeong ◽  
Dae-Yup Shin ◽  
Young-Woo Song ◽  
...  
Keyword(s):  
Energy Levels ◽  
Luminous Efficiency ◽  
Coupling Reactions ◽  
Blue Fluorescence ◽  
Lumo Energy ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Hole Transporting ◽  
Palladium Catalyzed ◽  
Hole Transporting Material

ABSTRACTBoth luminous efficiency and lifetime in blue fluorescence organic light emitting devices (OLEDs) have been improved by modified HTMs with higher LUMO energy levels. The LUMO energy levels of HTM were increased by modifying substituent in HTM molecules. Two HTMs containing ortho and meta biphenyl substituent and one HTM containing thiophene substituent were synthesized via palladium catalyzed amine coupling reactions to compare with a para biphenyl substituent HTM-1 as a standard molecule. According to TDDFT calculations, these three modified HTMs showed 0.05-0.15 eV higher LUMO energy levels compared to the para biphenyl substituent HTM-1. The luminous efficiency and the lifetime (LT90) of OLEDs using HTM-2 at 500 cd/m2 have been enhanced up to 20 % and 52 %, respectively, compared to the standard device using HTM-1.

Theoretical Investigation of Organic Amines as Hole Transporting Materials: Correlation to the Hammett Parameter of the Substituent, Ionization Potential, and Reorganization Energy Level

2009 ◽  
Vol 62 (5) ◽  
pp. 483 ◽  
Author(s):  
Jiunn-Hung Pan ◽  
Yu-Ma Chou ◽  
Houn-Lin Chiu ◽  
Bo-Cheng Wang
Keyword(s):  
Radical Cation ◽  
Density Functional ◽  
Reorganization Energy ◽  
Hole Transport ◽  
Substitution Effects ◽  
Oxidation Potentials ◽  
Hole Transporting ◽  
Organic Amines ◽  
Hammett Parameter ◽  
Hole Transporting Materials

Theoretical calculations on organic amines widely used as hole-transporting materials (HTMs) in multilayer organic light-emitting diodes have been performed. The calculated Ip and the reorganization energy for hole transport (λ+) of triphenylamine (TPA), 9-phenyl-9H-carbazole (PC), and their derivatives, are found to be related to their Hammett parameter (σ). In this study, the density functional theory (DFT) calculation is used to optimize 82 TPA and PC derivatives. Electronic structures of these compounds in the neutral and the radical-cation states are obtained based on calculations on optimized geometrical structures. The Ip and λ+ values are derived from calculated heats of formation (or total energy) of the neutral and the radical-cation states. In particular, the calculated Ips for these derivatives correlate well with the experimental data. The substitution effect for the mono-substituted TPA and PC is displayed in that the Ips of the TPA and PC derivatives with electron-donating and -withdrawing substituents are lower and higher than those of TPA and PC, respectively. For the effect of substitution position, the para-substituted TPA derivatives have higher Ip and –EHOMO than those of meta-substituted TPAs. The substitution effects in di- and tri-substituted TPAs are more pronounced than that of mono-substituted ones. According to the results, the calculated Ips shows an excellent agreement with the experimental oxidation potentials (EP/2) in these TPA derivatives. Furthermore, these calculation results can be employed to predict electro-luminescent properties for new and improved HTMs.

A polymeric bis(di-p-anisylamino)fluorene hole-transport material for stable n-i-p perovskite solar cells

2021 ◽  
Author(s):  
Marie-Hélène Tremblay ◽  
Kelly Schutt ◽  
Yadong Zhang ◽  
Stephen Barlow ◽  
Henry J. Snaith ◽  
...  
Keyword(s):  
Solar Cells ◽  
Perovskite Solar Cells ◽  
Heat Stability ◽  
Hole Transport ◽  
Side Chains ◽  
Hole Transporting

Half-devices made with a norbornene homopolymer with hole-transporting 2,7-bis(di-p-anisylamino)fluorene side chains exhibit improved light and heat stability in comparison to those incorporating spiro-OMeTAD.

Regioselective Oxidative Cross-Coupling Reaction: Synthesis of Imidazo[1,2-a]pyridine Fluorophores

Synthesis ◽  
2021 ◽  
Author(s):  
Xianglong Chu ◽  
Yadi Niu ◽  
Chen Ma ◽  
Xiaodong Wang ◽  
Yunliang Lin ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
Cross Coupling Reaction ◽  
Color Tunable ◽  
Palladium Catalyzed ◽  
Structure Relationship ◽  
High Fluorescence

AbstractA rapid access to a series of N-heteroarene fluorophores has been developed on the basis of the palladium-catalyzed direct oxidative C–H/C–H coupling of imidazo[1,2-a]pyridines with thiophenes/furans. The photophysical properties–structure relationship was systematically investigated. The resulting N-heteroarene fluorophores present color-tunable emissions (λem: 431–507 nm in CH2Cl2) and high fluorescence quantum yields (up to 91% in CH2Cl2).

scholarly journals Step-saving synthesis of star-shaped hole-transporting materials with carbazole or phenothiazine cores via optimized C–H/C–Br coupling reactions

RSC Advances ◽  
2021 ◽  
Vol 11 (15) ◽  
pp. 8879-8885
Author(s):  
Jui-Heng Chen ◽  
Kun-Mu Lee ◽  
Chang-Chieh Ting ◽  
Ching-Yuan Liu
Keyword(s):  
Solar Cell ◽  
Perovskite Solar Cell ◽  
Hole Transport ◽  
Coupling Reactions ◽  
Hole Transporting ◽  
Shaped Hole ◽  
Hole Transporting Materials

Carbazole or phenothiazine core-based hole-transport materials are facilely accessed by an optimized synthesis-shortcut. Perovskite solar cell devices with 6–13 demonstrate PCEs of up to 17.57%.

scholarly journals The role of L/W in the solar radiation for Saharian cities

2019 ◽  
Vol 91 ◽  
pp. 05006
Author(s):  
Rami Qaoud ◽  
Alkama Djamal
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Energy Levels ◽  
Direct Solar Radiation ◽  
Test Field ◽  
Natural Lighting ◽  
The Difference ◽  
The Impact ◽  
The Relationship

The urban fabric of the desert cities is based on the principle of reducing the impact of urban canyons on direct solar radiation. Here comes this research, which is based on a comparative study of the periods of direct solarisation and values of the solar energy of urban canyons via two urban fabrics that have different building densities, where the ratio between L/W is different. In order to obtain the real values of the solar energy (thermal, lighting), the test field was examined every two hours, each three consecutive days. The measurement stations are positioned by the three types of the relationship between L/W, (L≥2w, L=w, L≤0.5w). According to the results, we noticed and recorded the difference in the periods of direct solarization between the types of urban engineering canyons, reaching 6 hours a day, the difference in thermal values of air, reaching 4 °C, and the difference in periods of direct natural lighting, reaching 6 hours. It should be noted that the role of the relationship between L/W is to protect the urban canyons by reducing the impact of direct solar radiation on urban canyons, providing longer hours of shading, and reducing solar energy levels (thermal, lighting) at the urban canyons. This research is classified under the research axis (the studies of external spaces in the urban environment according to the bioclimatic approach and geographic approach). But this research aims to focus on the tracking and studying the distribution of the solar radiation - thermal radiation and lighting radiation - in different types of street canyons by comparing the study of the direct solarization periods of each type and the quantity of solar energy collected during the solarization periods.

scholarly journals SPECTRAL CORRELATIONS IN DISORDERED MESOSCOPIC METALS AND THEIR RELEVANCE FOR PERSISTENT CURRENTS

1996 ◽  
Vol 10 (28) ◽  
pp. 1397-1406 ◽  
Author(s):  
AXEL VÖLKER ◽  
PETER KOPIETZ
Keyword(s):  
Energy Levels ◽  
Three Dimensional ◽  
Average Density ◽  
Electron Interaction ◽  
Energy Window ◽  
Persistent Currents ◽  
Dependent Part ◽  
The Difference ◽  
Aharonov Bohm ◽  
Grand Canonical

We use the Lanczos method to calculate the variance σ2(E, ϕ) of the number of energy levels in an energy window of width E below the Fermi energy for noninteracting disordered electrons on a thin three-dimensional ring threaded by an Aharonov–Bohm flux ϕ. We confirm numerically that for small E the flux-dependent part of σ2(E, ϕ) is well described by the Altshuler–Shklovskii-diagram involving two Cooperons. However, in the absence of electron–electron interactions this result cannot be extrapolated to energies E where the energy-dependence of the average density of states becomes significant. We discuss consequences for persistent currents and argue that for the calculation of the difference between the canonical- and grand canonical current it is crucial to take the electron–electron interaction into account.

Spectroscopic Investigations of Electron and Hole Dynamics in MAPbBr3 Perovskite Film and Carrier Extraction to PEDOT Hole Transport Layer

2021 ◽  
Author(s):  
Dariusz M. Niedzwiedzki ◽  
Mojgan Kouhnavard ◽  
Yifan Diao ◽  
Julio M. D'Arcy ◽  
Pratim Biswas
Keyword(s):  
Room Temperature ◽  
Hole Transport ◽  
Transport Layer ◽  
Oxide Glass ◽  
Hole Transport Layer ◽  
Hole Transporting ◽  
Halide Perovskite ◽  
Vapor Phase Polymerization ◽  
Carrier Extraction ◽  
Steady State Absorption

Organometallic halide perovskite (MAPPbBr3), Rust-based Vapor Phase Polymerization (RVPP)-PEDOT hole transporting layers and (RVPP-PEDOT)/MAPPbBr3 dual-layer, deposited on fluorine doped tin oxide glass were studied at room temperature using steady-state absorption,...

scholarly journals Progress on the Synthesis and Application of CuSCN Inorganic Hole Transport Material in Perovskite Solar Cells

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2592 ◽  
Author(s):  
Funeka Matebese ◽  
Raymond Taziwa ◽  
Dorcas Mutukwa
Keyword(s):  
Solar Cells ◽  
Energy Levels ◽  
Perovskite Solar Cells ◽  
Hole Mobility ◽  
Cost Effective ◽  
Vital Role ◽  
Hole Transport ◽  
Recombination Processes ◽  
Short Synthesis ◽  
P Type

P-type wide bandgap semiconductor materials such as CuI, NiO, Cu2O and CuSCN are currently undergoing intense research as viable alternative hole transport materials (HTMs) to the spiro-OMeTAD in perovskite solar cells (PSCs). Despite 23.3% efficiency of PSCs, there are still a number of issues in addition to the toxicology of Pb such as instability and high-cost of the current HTM that needs to be urgently addressed. To that end, copper thiocyanate (CuSCN) HTMs in addition to robustness have high stability, high hole mobility, and suitable energy levels as compared to spiro-OMeTAD HTM. CuSCN HTM layer use affordable materials, require short synthesis routes, require simple synthetic techniques such as spin-coating and doctor-blading, thus offer a viable way of developing cost-effective PSCs. HTMs play a vital role in PSCs as they can enhance the performance of a device by reducing charge recombination processes. In this review paper, we report on the current progress of CuSCN HTMs that have been reported to date in PSCs. CuSCN HTMs have shown enhanced stability when exposed to weather elements as the solar devices retained their initial efficiency by a greater percentage. The efficiency reported to date is greater than 20% and has a potential of increasing, as well as maintaining thermal stability.

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