New m-MTDATA skeleton-based hole transporting materials for multi-resonant TADF OLEDs

Area of Science:

• Organic electronics
• Materials science
• Photophysics

Background:

• Hole transporting materials (HTMs) are crucial for organic light-emitting diodes (OLEDs).
• m-MTDATA is a commercially available core for HTMs, but improvements are sought.
• Developing efficient HTMs is key to advancing OLED technology.

Purpose of the Study:

• To synthesize and characterize new HTMs based on the m-MTDATA core.
• To investigate the impact of electron-donating groups on material properties.
• To evaluate the performance of these new HTMs in multi-resonant Thermally Activated Delayed Fluorescence (MR-TADF) OLEDs.

Main Methods:

• Synthesis of six new m-MTDATA derivatives using Buchwald-Hartwig amination.
• Experimental investigation of thermal, optical, photoelectrical, and charge transport properties.
• Fabrication and testing of OLED devices incorporating the synthesized HTMs.

Main Results:

• Synthesized compounds exhibited comparable ionization potentials to m-MTDATA.
• One derivative showed a hole mobility of 1.06 × 10^-3 cm^2 V^-1 s^-1, exceeding that of m-MTDATA.
• OLEDs utilizing the new HTMs and a deep-blue MR-TADF emitter achieved high external quantum efficiency (13.8%) and excellent color purity.

Conclusions:

• The synthesized m-MTDATA derivatives are promising HTMs for advanced OLED applications.
• Electron-donating groups can be effectively used to tune the properties of m-MTDATA-based HTMs.
• These novel materials contribute to the development of high-performance, efficient OLED devices.