Highly Efficient Red/Near-Infrared Phosphorescence from Doped Crystals

Area of Science:

• Materials Science
• Organic Chemistry
• Photophysics

Background:

• Organic red/near-infrared (NIR) room temperature phosphorescence (RTP) materials are crucial for biotechnology and encryption.
• Challenges in achieving efficient organic RTP include weak spin-orbit coupling and nonradiative decay.
• Existing methods struggle to produce low-toxicity, easily synthesized long-wavelength RTP emitters.

Purpose of the Study:

• To develop highly efficient red/NIR RTP materials with improved quantum yields.
• To investigate the mechanism of enhanced RTP through doping phthalimide (PAI) derivatives.
• To explore the potential applications of these novel RTP materials.

Main Methods:

• Synthesized thionated phthalimide derivatives (MTPAI and DTPAI).
• Doped MTPAI and DTPAI into PAI crystals to create host-guest systems.
• Characterized photoluminescence (PL) properties, including quantum yields (Φ_ps) and emission spectra.

Main Results:

• Achieved highly efficient red/NIR RTP with quantum yields up to 32.96%.
• Observed red-shifted PL attributed to the external heavy atom effect and emissive sulfur-centered clusters.
• Demonstrated enhanced exciton generation and energy transfer within the doped crystals.

Conclusions:

• Doping PAI crystals with thionated derivatives is a universal strategy for efficient long-wavelength RTP.
• The developed materials show promise for applications in optical waveguides and encryption.
• This work provides valuable insights into host-guest interactions for tuning photophysical properties.