Near-infrared-to-deep-blue photon upconversion engineered from PbS quantum dots and perylene derivatives

Area of Science:

• Materials Science
• Photochemistry
• Quantum Dot Technology

Background:

• Triplet-triplet annihilation photon upconversion (TTA-UC) is crucial for solar energy, photochemistry, and bioimaging.
• Achieving large anti-Stokes shifts from NIR to blue light via TTA-UC remains a significant challenge.

Purpose of the Study:

• To develop the first TTA-UC system capable of upconverting NIR light (beyond 800 nm) to the deep-blue spectral region.
• To engineer a system with a large apparent anti-Stokes shift for advanced applications.

Main Methods:

• Utilized PbS quantum dots (QDs) as sensitizers, perylene-3-carboxylic acid (3-PYCA) as a novel mediator, and perylene as an annihilator.
• Precisely engineered triplet energy levels within 0.06 eV among the components.
• Investigated the upconversion efficiency and anti-Stokes shift of the developed system.

Main Results:

• Achieved NIR-to-deep-blue photon upconversion with excitation beyond 800 nm and emission in the deep-blue region.
• Demonstrated a record anti-Stokes shift of up to 1.3 eV, the maximum for QD-based TTA-UC systems.
• Obtained a high TTA-UC quantum yield of 2.1%, an order of magnitude higher than previous systems with large anti-Stokes shifts.
• Successfully triggered cis-to-trans photoisomerization of azobenzene using the upconverted deep-blue light.

Conclusions:

• The developed TTA-UC system represents a breakthrough in NIR-to-blue light conversion, offering record-breaking performance.
• The system's ability to generate deep-blue light from NIR excitation opens new possibilities for NIR-triggered photochemistry.
• This advancement holds significant potential for applications in solar energy, bioimaging, and photochemical transformations.