Narrowband Emissive TADF Conjugated Polymers towards Highly Efficient Solution-Processible OLEDs

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Chemistry

Background:

• Thermally Activated Delayed Fluorescence (TADF) conjugated polymers typically exhibit broad emission spectra.
• Broad emission spectra result from significant structural relaxation, limiting their use in high-quality organic light-emitting diode (OLED) displays.

Purpose of the Study:

• To engineer TADF conjugated polymers with narrowband emission characteristics.
• To improve the spectral purity of TADF polymers for advanced OLED applications.

Main Methods:

• Synthesized polycarbazole backbone polymers functionalized with multiple resonance (MR) induced emitting moieties as pendant groups.
• Characterized the photophysical properties of the synthesized TADF polymers, focusing on emission spectra and full-width at half-maximum (FWHM).
• Fabricated solution-processed OLED devices using the synthesized polymers as emissive layers.

Main Results:

• The novel TADF conjugated polymers demonstrated narrowband emission with FWHMs ranging from 33-43 nm.
• The polymers exhibited typical TADF characteristics.
• OLED devices achieved a maximum external quantum efficiency (EQE) of 17.5%, with emission peaking at 496 nm and an FWHM of 34 nm.

Conclusions:

• Attaching MR-induced emitting moieties effectively suppresses spectral broadening in TADF conjugated polymers.
• The developed polymers are promising materials for high-performance, solution-processed OLED displays requiring narrowband emission.