Triplet-Mediated Photon Upconversion via Near-Infrared-II Excitation without Tetracene Derivatives

Area of Science:

• Materials Science
• Nanotechnology
• Photonics

Background:

• Traditional triplet-mediated photon upconversion materials often use tetracene derivatives.
• Tetracene derivatives suffer from poor stability and limited energy tunability, hindering progress in NIR-excitable upconversion.
• There is a need for stable, tunable materials for efficient triplet-sensitized photon upconversion.

Purpose of the Study:

• To develop a novel material for near-infrared (NIR) photon upconversion.
• To overcome the limitations of tetracene derivatives in stability and tunability.
• To enable efficient and color-tunable upconversion in quantum dots under NIR excitation.

Main Methods:

• Synthesized a distyryl-substituted BODIPY (DS-BDP) derivative with dicarboxylic acid anchoring groups.
• Utilized DS-BDP as both a surface ligand and an annihilator for quantum dots.
• Investigated triplet exciton transfer and energy loss mechanisms in the upconversion process.
• Evaluated upconversion efficiency under 1064 nm excitation.

Main Results:

• The DS-BDP derivative demonstrated exceptional stability and spectral tunability.
• Efficient triplet exciton transfer from quantum dots to DS-BDP ligands was achieved.
• Suppression of excited-state energy losses due to ligand conformational relaxation was observed.
• High upconversion efficiency was maintained even at low surface ligand coverage.

Conclusions:

• The developed DS-BDP derivative overcomes the limitations of tetracene-based upconversion materials.
• This work establishes a robust platform for stable, high-performance NIR-II-excitable quantum dot-based upconversion.
• The material shows significant potential for applications in nanophotonics, biophotonics, and photochemistry.