Atomically resolved single-molecule triplet quenching

Area of Science:

• Physical Chemistry
• Surface Science
• Molecular Physics

Background:

• The nonequilibrium triplet state is crucial for applications like photocatalysis, organic photovoltaics, and photodynamic therapy.
• Understanding and controlling molecular triplet states is essential for optimizing these technologies.

Purpose of the Study:

• To directly measure the triplet lifetime of an individual pentacene molecule on an insulating surface with atomic resolution.
• To investigate the effect of coadsorbed oxygen molecules on the triplet lifetime of pentacene.
• To establish a correlation between molecular arrangements and triplet state quenching.

Main Methods:

• Development and application of an electronic pump-probe method integrated with atomic force microscopy (AFM).
• Utilizing single-molecule manipulation techniques for precise arrangement of pentacene and oxygen molecules.
• Atomic-resolution characterization of molecular configurations and their impact on triplet lifetimes.

Main Results:

• Direct measurement of the triplet lifetime of individual pentacene molecules achieved.
• Significant quenching of the triplet lifetime observed when oxygen molecules are in close proximity to pentacene.
• Precise correlation established between specific molecular arrangements and the degree of triplet state quenching.

Conclusions:

• The study demonstrates a method for electrically addressing and controlling long-lived triplet states in single molecules.
• Atomic-scale manipulation combined with lifetime measurements provides new insights into local spin-spin interactions.
• This approach opens avenues for designing and controlling molecular properties for advanced quantum and materials applications.