MR-TADF Materials

Multiple Resonance Thermally Activated Delayed Fluorescence (MR-TADF) materials represent a cutting-edge approach in OLED material design. Compared to traditional donor-acceptor (D–A) TADF materials, MR-TADF molecules achieve spatial separation and energy proximity between the HOMO and LUMO by alternately embedding electron-deficient atoms (such as boron (B)) and electron-rich atoms (such as nitrogen (N)) within a rigid aromatic backbone. This MR-TADF exhibits the following key advantages:

• Extremely narrow fluorescence/electroluminescence (EL) spectra (typical FWHM < 40 nm).
• High photoluminescence quantum yield (PL QY) and excellent color purity.
• The ability to achieve thermally activated reverse intersystem crossing (RISC) of triplet excited states, enabling more efficient utilization of singlet and triplet excitons in electrically excited states.
• Ideally, they are ideal for high-resolution, wide-color-gamut display and solid-state lighting applications.

Fig. 1 Molecular structures of some MR-TADF materials^[1].

In this context, Alfa Chemistry has launched a series of representative products under the MR-TADF material category, covering multiple main skeletons such as DABNA, CzBN, DiKTa, etc., to meet the needs from deep blue, blue, green to near-red spectra.

Catalog	Name
ACM1689552893-1	DABNA-1
ACM1802003071-1	t-DABNA
ACM2170487304-1	DtBuCzB
ACM2251782133-2	v-DABNA
ACMA00020883	3tPAB
ACMA00020884	CzBN
ACMA00020887	DOBNA-OAr
ACMA00020890	TB-P3Cz
ACMA00020929	TB-tPCz
ACMA00020930	t-Bu-ν-DABNA
ACMA00020931	TDBA-SAF
ACMA00020932	tDPA-DtCzB
ACMA00020933	2PTZBN
ACMA00020934	3TPA-DiKTa
ACMA00020939	BN-CP1
ACMA00020941	Mes3DiKTa
ACMA00020944	3DPA-DiKTa
ACMA00020951	mMDBA-DI
ACMA00020963	DiKTa

MR-TADF Material Classification and Structural Characteristics

Alfa Chemistry's MR-TADF material system primarily encompasses three molecular design routes: DABNA-based blue-emitting materials, CzBN-based multi-resonance boron-nitrogen emitters, and extended structures such as DiKTa. While these materials differ in structure and energy level distribution, they all achieve narrow-spectrum, high-efficiency, and highly stable electroluminescence characteristics based on the multi-resonance effect.

DABNA-Based Materials

This series, exemplified by DABNA-1, achieves precise separation and energy-level control of the HOMO and LUMO by alternately embedding B/N atoms within a rigid aromatic ring backbone. These molecules exhibit extremely high photoluminescence quantum yields (PL QY > 0.85) and extremely narrow emission spectra (FWHM ≈ 25–30 nm), primarily for applications in deep-blue and pure-blue OLED emissive layers. DABNA, t-DABNA, v-DABNA, and their derivatives demonstrate excellent EQE and stability in high-color-purity displays.

Fig. 2 Chemical structure of the ν-DABNA-derived blue MR-TADF emitter^[2].

CzBN-Based Materials

CzBN and its derivatives (such as DtBuCzB and tDPA-DtCzB) combine carbazole donors with boron-nitrogen multi-resonance acceptor units, combining electron transport capabilities with a rigid molecular framework. These molecules exhibit high thermal stability and device compatibility in the mid-blue to blue-green emission range, making them suitable for high-brightness, long-lifetime display devices.

Fig. 3 a) Molecular structures of CzBN, CzBNNa, and CzBNPyr and their corresponding DFT calculations based on B3LYP/6-31G+(d, p). b) Photophysical properties of CzBN, CzBNNa, and CzBNPyr in toluene solution^[3].

Extended Multi-Resonance Structures

By introducing heteroaryl groups (such as PTZ and tPCz) or extending the aromatic ring system (such as the DiKTa backbone) into the MR-TADF framework, the molecular resonance paths can be further tuned, achieving a continuous range of emission from blue to green and even orange-red. For example, DiKTa, 3DPA-DiKTa, and Mes3DiKTa represent the latest developments in multi-resonance-donor hybrid emitters, combining high efficiency with tunable color tone.

Alfa Chemistry also offers a variety of structurally modified compounds, such as DOBNA-OAr, TDBA-SAF, and mMDBA-DI, for exploring device requirements for higher color purity, improved thermal stability, or more precise color coordinate control. All materials undergo rigorous purification and quality testing to ensure consistency and reproducibility in OLED research and device development.

Applications and Advantages

• High-Color-Purity Displays: MR-TADF materials typically feature narrow emission peaks and small spectral widths, facilitating the achievement of the BT.2020 color gamut or wider display standards.
• High-Performance OLED Devices: Through high PL QY and high k_RISC, MR-TADF is expected to achieve high external quantum efficiency (EQE) and low efficiency rolloff in these devices.
• Subsequent Device Integration: Suitable for ultra-high-resolution microdisplays (such as VR/AR), broadcast-grade TV panels, professional lighting, and fluorescent probes for bioimaging.
• Customized R&D: Alfa Chemistry can customize MR-TADF molecules based on customer requirements, such as target emission wavelength, spectral width, device lifetime requirements, molecular stability, and crystal purity.

Why Choose Alfa Chemistry MR-TADF Materials?

• Deep Industry Experience: Leveraging years of expertise in organic light-emitting materials, Alfa Chemistry can provide high-purity MR-TADF molecules that meet stringent device-level requirements.
• Strict Quality Control: Our MR-TADF materials undergo high-temperature sublimation or other purification processes to ensure ultra-high purity (>99%), minimizing the impact of impurities on device performance.
• Comprehensive Product Line: Covering MR-TADF molecules with emission ranges from deep blue to blue to green to near-red, allowing flexible selection based on project requirements.
• Technical Support: Provides material parameter data (such as ΔE⁻ST, PL QY, fluorescence peak, FWHM, and device examples), synthetic route recommendations, and device packaging formulation guidance.
• Strong Customization Capabilities: We collaborate with customers on R&D for specialized color gamuts, ultra-narrow spectral widths, and enhanced stability (e.g., through substituent modification or molecular rigidity design).

Contact us for product technical information, quotes, and customized solutions. Let Alfa Chemistry be your trusted partner in high-performance organic light-emitting materials.

References

1. Wu X., et al. The role of host–guest interactions in organic emitters employing MR-TADF. Nature Photonics, 2021, 15(10), 780-786.
2. Konidena RK, et al. Boron‐Based Narrowband Multiresonance Delayed Fluorescent Emitters for Organic Light‐Emitting Diodes. Advanced Photonics Research, 2022, 3(11), 2200201.
3. Lee Y-T, et al. Tailor‐Made Multi‐Resonance Terminal Emitters toward Narrowband, High‐Efficiency, and Stable Hyperfluorescence Organic Light‐Emitting Diodes. Advanced Optical Materials, 2022, 10(17), 2200682.