Pressure-Driven Photoluminescence Spectral Narrowing in X-Aggregates Dye via Self-Absorption Effect

Area of Science:

• Materials Science
• Photophysics
• Organic Electronics

Background:

• Piezochromic materials usually show spectral broadening and photoluminescence (PL) quenching under pressure.
• Achieving pressure-induced spectral narrowing in organic systems is a significant challenge.

Purpose of the Study:

• To report the first observation of pressure-driven PL spectral narrowing in organic ZPH crystals.
• To elucidate the mechanisms behind this counterintuitive phenomenon.

Main Methods:

• Synthesis and characterization of ZPH crystals.
• Hydrostatic pressure experiments on ZPH crystals.
• Analysis of photoluminescence spectra and absorption-PL spectral overlap under pressure.

Main Results:

• Observed pressure-driven PL spectral narrowing in ZPH crystals.
• Found increased absorption-PL spectral overlap under hydrostatic pressure.
• Identified weakened X-aggregate exciton coupling below 8.93 GPa, enhancing a PL shoulder peak.

Conclusions:

• Leveraging self-absorption offers a novel strategy for controlling spectral properties.
• The interplay between self-absorption and exciton coupling governs pressure-induced spectral narrowing.
• This study advances the understanding of photophysical properties under pressure.