Photon upconversion with indium phosphide quantum dots enables high-energy photoreactions using visible light

Area of Science:

• Photochemistry
• Materials Science
• Sustainable Chemistry

Background:

• Traditional photochemistry relies on high-energy UV light, limited by solar abundance and causing unwanted decomposition.
• Photon upconversion offers a path to use abundant visible/NIR light for UV-driven reactions.
• Quantum dot (QD)-sensitized triplet-triplet annihilation-based upconversion (TTA-UC) shows promise for enhanced efficiency and stability.

Purpose of the Study:

• To utilize QD-sensitized TTA-UC for high-energy photochemical transformations typically requiring UV light.
• To demonstrate a sustainable, low-energy alternative to conventional UV photochemistry.
• To explore the application of this system in dehalogenation and polymerization reactions.

Main Methods:

• Employed Indium phosphide (InP) quantum dots as sensitizers and diphenylanthracene (DPA) as the annihilator for TTA-UC.
• Generated green-to-blue upconversion with a ~8.2% quantum yield and 0.55 eV anti-Stokes shift.
• Applied the upconverted energy to drive photoredox dehalogenation and radical polymerization reactions.

Main Results:

• Successfully performed high-energy dehalogenation of aryl halides via photoredox C-C coupling using visible light.
• Achieved excellent yields in the dehalogenation reaction, driven solely by TTA-UC energy.
• Demonstrated the system's capability for radical polymerization of methyl methacrylate (MMA) to produce PMMA.

Conclusions:

• QD-sensitized TTA-UC provides an effective pathway for visible-light-driven high-energy photochemical reactions.
• This approach overcomes limitations of UV photochemistry, offering a sustainable and efficient alternative.
• The system shows broad applicability in catalysis and polymer synthesis, paving the way for greener chemical processes.