Excimer of Perylene in a Xerogel Matrix Shows Both Solution- and Solid-Like Dynamics

Area of Science:

• Materials Science
• Organic Electronics
• Photophysics

Background:

• Fluorescence quenching in solid-state optoelectronics is a major challenge for polyaromatic hydrocarbons (PAHs).
• Aggregation-caused quenching (ACQ) in PAHs like perylene reduces their efficiency in devices.
• Xerogel matrices offer a potential solution for embedding and stabilizing PAHs.

Purpose of the Study:

• To develop a cost-effective method to mitigate perylene's ACQ using a xerogel matrix.
• To investigate the optical properties and exciton dynamics of perylene within a xerogel.
• To explore the potential of cholesteryl-based matrices for solid-state emission in optoelectronics.

Main Methods:

• Coassembling perylene with a low-molecular-weight gelator (cholesteryl chloroformate and pentaerythritol) to form a xerogel.
• Comparative studies of perylene in powder, solution, and xerogel using various concentrations.
• Employing steady-state and time-resolved emission spectroscopy, including time-resolved area-normalized emission spectra (TRANES).

Main Results:

• Perylene in xerogel exhibits emissions from both monomeric and excimer states.
• Exciton dynamics reveal emission from a Y-state (570 nm) relaxing to an excimer state (595 nm) within the xerogel.
• TRANES shows single-step monomer-excimer interconversion in powder and solution, with distinct emission peaks and isoemissive points.

Conclusions:

• Coassembling perylene with a cholesteryl-based gelator in a xerogel matrix effectively reduces ACQ.
• The xerogel matrix allows for tuning optical properties by controlling exciton dynamics.
• Cholesteryl-based host matrices show promise for maintaining solid-state emission in organic optoelectronic applications.