Thermally Activated Upconversion with Metal-Free Sensitizers Enabling Exceptional Anti-Stokes Shift and...

Area of Science:

• Materials Science
• Photochemistry
• Organic Electronics

Background:

• Photochemical upconversion (UC) via triplet-triplet annihilation (TTA) is promising for solar energy, photocatalysis, and bioimaging.
• Achieving large anti-Stokes shifts in UC, especially with organic sensitizers, remains a significant challenge.

Purpose of the Study:

• To develop solid-state TTA UC systems using metal- and heavy atom-free organic dyes.
• To achieve significant anti-Stokes shifts and air-stable UC emission.

Main Methods:

• Utilized purely organic dyes as sensitizers for 9,10-diphenylanthracene acceptor.
• Employed thermally activated triplet-triplet energy transfer for sensitization.
• Developed solid-state UC systems.

Main Results:

• Achieved solid-state UC emission with anti-Stokes shifts up to 1.10 eV.
• Demonstrated air-stable UC emission from the developed upconverter.
• Showcased potential for dual-mode anti-counterfeiting and encryption.

Conclusions:

• The developed UC approach offers a versatile strategy for TTA UC materials with large anti-Stokes shifts.
• Purely organic dyes enable air-tolerant emission and environmental compatibility.
• Promising applications in information encryption, photochemical conversion, and bioimaging are anticipated.