Two-Photon Ionization Induced Stable White Organic Long Persistent Luminescence.

Area of Science:

• Materials Science
• Organic Chemistry
• Photophysics

Background:

• Organic long persistent luminescence (OLPL) materials with extended afterglow durations are scarce.
• Existing exciplex-based OLPL systems often require complex multi-component designs for white emission, compromising stability and duration.

Purpose of the Study:

• To develop a simple binary OLPL system capable of long-lasting, stable white afterglow.
• To investigate a two-photon ionization mechanism for efficient exciton harvesting.
• To tune emission profiles for various white light applications.

Main Methods:

• Fabrication of a binary OLPL system using a dibenzo[b,d]thiophen-2-yldiphenyl phosphine oxide host.
• Incorporation and optimization of dopant molecules.
• Characterization of afterglow duration, color coordinates, and stability.

Main Results:

• Achieved OLPL with afterglow durations ranging from 20 to 40 minutes.
• Demonstrated a simple binary system based on two-photon ionization mechanism.
• Successfully tuned afterglow colors from cyan to various white shades (cold, standard, warm) with high color consistency.

Conclusions:

• The developed binary OLPL system offers a promising route to stable, long-lasting white afterglow.
• The two-photon ionization mechanism efficiently harvests both singlet and triplet excitons.
• Tunable emission profiles make these materials versatile for applications requiring stable white light.