Dendronized Encapsulation with Hierarchical Rigidification Enabling Robust Solution Room-Temperature Phosphorescence,...

Area of Science:

• Materials Science
• Organic Electronics
• Photophysics

Background:

• Organic room-temperature phosphorescence (RTP) materials typically exhibit environment-dependent behavior, limiting their use in multifunctional applications.
• A key challenge is developing RTP materials that maintain performance across diverse conditions, including solution and solid states.

Purpose of the Study:

• To overcome the environmental limitations of RTP materials.
• To develop a single material system with adaptive, environment-independent RTP properties.
• To establish universal design principles for advanced luminescent materials.

Main Methods:

• Engineered dendronized donor-acceptor molecules with alkyl-chain-carbazole dendrons for intramolecular flexible encapsulation.
• Implemented multiscale confinement through molecular aggregation and poly(methyl methacrylate) (PMMA) doping for intermolecular rigid immobilization.
• Investigated suppression of nonradiative transitions across a wide temporal range (10^-3–10⁰ s).

Main Results:

• Achieved a solution-phase RTP lifetime of ≈9 ms under ambient conditions, the longest reported for solution-dissolved RTP systems.
• Demonstrated high photoluminescence quantum yield (72%) in doped films and external quantum efficiency (17.2%) in organic light-emitting diodes (OLEDs).
• Observed ultralong afterglow with 1.16 s persistent RTP and 10 s naked-eye-detectable emission.

Conclusions:

• Developed a novel multiscale confinement strategy integrating intramolecular and intermolecular interactions for adaptive RTP materials.
• Successfully demonstrated a single material system exhibiting solution-phase RTP, high-efficiency electroluminescence, and long afterglow.
• Established a universal design principle for creating environment-adaptive luminescent materials for optoelectronic applications.