TCTA;4,4′,4”-Tris(carbazol-9-yl)-triphenylamine CAS-no-139092-78-7_News

TCTA (CAS: 139092-78-7) :A High-Performance Carbazole-Triphenylamine Host Material for OLEDs
1、 Product Overview
TCTA, chemically known as 4,4′,4″-Tris(carbazol-9-yl)triphenylamine, is a multifunctional organic semiconductor material widely recognized as a high-performance host and hole-transport material in organic optoelectronic devices . 
TCTA features a distinctive tri-carbazole-substituted triphenylamine structure that combines an electron-rich triarylamine core with three carbazole pendant groups .
This unique molecular architecture delivers a rare combination of properties: efficient hole mobility, high triplet energy, excellent thermal and morphological stability, and strong film-forming capability . 
Since its introduction, TCTA has become a benchmark material in phosphorescent OLED (PhOLED) development, particularly for green and sky-blue emitters, where its high triplet energy (2.78 eV) effectively confines triplet excitons within the emissive layer.
TCTA (CAS: 139092-78-7) stands as a cornerstone material in organic electronics, distinguished by its high triplet energy, excellent thermal stability, and versatile processability. 
From enabling record-efficiency phosphorescent OLEDs to serving as a stable organic battery cathode, TCTA continues to demonstrate exceptional utility across multiple advanced technology platforms.

2、 Basic Product Information
CAS number:          139092-78-7
Chemical formula:  C54H36N4
Molecular weight:   740.89 g/mol
Absorption:             λmax 293 and 326 nm (THF)
Fluorescence:        λem 385 nm (THF)
HOMO/LUMO :      HOMO = 5.83 eV, LUMO = 2.43 eV [1]
Synonyms:             TCTA, 4,4',4"-Tris(carbazol-9-yl)triphenylamine; Tris(4-carbazoyl-9-ylphenyl)amine
Classification / Family :   Carbazole derivatives, Hole-injection layer materials, Hole-transporting layer materials, Phosphorescent host materials, Electron-blocking layer materials, Light-emitting diodes
Purity:                            >99.5% (sublimed)
                                      >98.0% (unsublimed)
Melting point:                 298~300 °C
Appearance:                  White powder/crystals
Product Manager Email: Joy@coreychem.com

3、 Frequently Asked Questions (FAQ)
Q1:Why does TCTA offer superior thermal and morphological stability?
TCTA's rigid tri-carbazole architecture delivers a high glass transition temperature of about 151 °C (some sources report >140 °C), ensuring amorphous film stability under Joule heating and during annealing . 
This high Tg directly addresses device degradation issues seen in lower-Tg hole-transport materials such as NPB and TPD (Tg ≈ 95–100 °C), which are prone to crystallization and interlayer diffusion during operation . 
The result is longer device lifetime and better manufacturing yield.
Q2:What makes TCTA suitable for solution-processed OLED fabrication?
TCTA demonstrates favorable solubility characteristics that enable solution-based device fabrication. It dissolves readily in solvents such as chlorobenzene, chloroform, dichloromethane, and THF . 
Research on inkjet-printed PhOLEDs has shown that TCTA functions effectively as a main host in mixed-host emissive layers, with good solubility in chlorobenzene at concentrations suitable for ink formulation . 
The material's relatively low polarity, arising from its symmetric molecular structure, requires careful solvent selection, but its compatibility with common aromatic solvents makes it viable for scalable printing processes. 
This solution-processability is essential for reducing manufacturing costs in large-area OLED displays and lighting panels.
Q3:How does TCTA contribute to extended device lifetimes?
TCTA's contribution to device longevity stems from multiple factors. First, its high Tg and morphological stability prevent degradation pathways associated with film crystallization . 
Second, when used in exciplex hosts, TCTA enables barrier-free charge injection and reduces the charge-trapping effects that accelerate device aging . 
Third, its high triplet energy minimizes exciton quenching at the host-dopant interface. The TCTA:3P-T2T exciplex system demonstrated a τ₈₀ lifetime 56 times longer than reference TCTA:B3PYMPM devices, underscoring the material's role in stabilizing device operation.
Q4:How does TCTA enhance charge transport and reduce driving voltage?
TCTA exhibits a deep HOMO level of approximately 5.7–5.8 eV and a hole mobility of about 1.9 × 10⁻⁴ cm²/V·s . In head-to-head hole-only device comparisons, TCTA demonstrated roughly 2.3× higher hole mobility than NPB (8.1 × 10⁻⁵ cm²/V·s), 
along with lower trap density and shallower characteristic trap depth . This efficient hole injection and transport supports low driving voltages and reduced resistive heating.
Q5: Why should TCTA not be blindly replaced by in-class analogs?
Though NPB, TPD, CBP, and mCP belong to the same triarylamine/carbazole class, they differ critically from TCTA in Tg, hole mobility, and energy-level alignment . 
Substituting TCTA with lower-Tg NPB/TPD risks morphological instability and interlayer diffusion, while replacing it with CBP can cause inferior triplet-energy confinement and reduced device efficiency . 
TCTA's specific combination of hole mobility, thermal robustness, and deep-HOMO/high-triplet alignment is not universally shared by its analogs, making blind substitution a direct risk to performance and yield.
4、 Application Cases
1)Phosphorescent OLED Host for Green and Sky-Blue Emitters
TCTA serves as a benchmark host material for green and sky-blue phosphorescent OLEDs. 
Its high triplet energy (2.78 eV) effectively confines triplet excitons within the emissive layer, while its hole-transporting carbazole groups facilitate balanced charge transport . 
Devices employing TCTA as a host have achieved external quantum efficiencies approaching 30% when paired with appropriate electron-transporting co-hosts.

2)Hole-Transport Layer (HTL) in Green/Red Phosphorescent OLEDs
Leveraging its deep HOMO alignment and high triplet energy, HTT serves as the HTL in green and red phosphorescent devices . 
A green device (ITO/NPD/TCTA/BCPO:Ir(ppy)₃/BCP/Alq₃/LiF/Al) achieved a maximum EQE of 21.6% and a max luminance of 207,839 cd/m², while a red device (Ir(piq)₃) reached 17% EQE and 2.7 V turn-on voltage.

3)Hole-Transport/Injection Material in Perovskite Solar Cells and Organic Light-Emitting Transistors
Beyond diodes, TCTA's deep HOMO (~-5.8 eV) optimizes energy alignment and maximizes open-circuit voltage in perovskite solar cells . 
It is also blended with emitters (e.g., TCTA:Ir(ppy)₃) as the emissive layer in organic light-emitting transistors (OLETs) with polymer gate dielectrics, giving improved performance and lower operating voltages.

4)Exciplex-Forming Co-Host for Thermally Activated Delayed Fluorescence (TADF) OLEDs
When blended with electron-transporting materials such as B3PYMPM, 3P-T2T, or CN-T2T, TCTA forms exciplex hosts that enable efficient TADF emission . 
A DACT-II-doped TCTA:B3PYMPM exciplex host achieved a maximum EQE of 34.2%, significantly higher than conventional CBP-based hosts . 
This application leverages TCTA's ability to facilitate reverse intersystem crossing and reduce efficiency roll-off.

5) Inkjet-Printed OLED Emissive Layers
TCTA has been successfully employed as a main host in inkjet-printed phosphorescent OLED emissive layers. In a mixed-host system with 3CzPFP, TCTA enabled orange-emitting PhOLED devices with EQE of 18% and current efficiency of 57.5 cd/A . 
The material's solubility profile and film-forming characteristics make it compatible with the viscosity and surface tension requirements of printhead nozzles.

For more questions and further information about the product, please contact:
Product Manager Email:Joy@coreychem.com