Triplet-triplet annihilation upconversion through triplet energy transfer at a nanoporous solid-liquid interface

Area of Science:

• Photochemistry
• Materials Science
• Nanotechnology

Background:

• Triplet-triplet annihilation (TTA) upconversion (UC) is a process that converts lower-energy photons to higher-energy photons.
• Efficient TTA-UC typically relies on homogeneous solutions, limiting its application in solid-state devices.

Purpose of the Study:

• To investigate TTA-UC via triplet energy transfer (TET) at a solid-liquid interface.
• To develop a robust system for TTA-UC using immobilized sensitizers.

Main Methods:

• Immobilization of a carboxylic-acid derivative of platinum-porphyrin sensitizer onto an amino-treated nanoporous glass surface.
• Photoexcitation at 532 nm and observation of UC emission from 9,10-diphenylanthracene (DPA) in solution.
• Analysis of TET dynamics using sensitizer phosphorescence decay and UC emission rise.

Main Results:

• Successful demonstration of TTA-UC at the solid-liquid interface.
• Identification of two TET components with rate constants slower than solution-based diffusion-controlled reactions.
• Achieved high quantum yield for UC emission at the solid-liquid interface.
• Fabrication of an all-solid TTA-UC system by incorporating DPA into the porous glass.

Conclusions:

• Solid-supported sensitizers can efficiently facilitate TTA-UC through TET at solid-liquid interfaces.
• The developed system offers a pathway for integrating TTA-UC into solid-state devices.
• The observed TET rates are sufficient for practical applications despite being slower than solution-based systems.