Investigating the Photostability and External Quantum Yield of Perylene Diimide Derivatives and the Effects of Carbon-Chain Length

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Physics and Astronomy

Date of Award

Spring 5-1-2026

Abstract

Perylene diimide (PDI) derivatives are high-performance organic chromophores valued for their strong absorption, high fluorescence quantum yields, and excellent photochemical stability. Despite their robustness, PDIs can experience quantum yield under continuous illumination; however, evidence from Fourier-transform infrared (FTIR) analysis indicates that their molecular structure remains intact after excitation, suggesting a potential for reversible photoluminescence recovery. This research investigated the quantum yield efficiency, matrix effects, and recovery kinetics of PDI derivatives with varying alkyl chain lengths (C3, C5 and C8), both in neat thin films and in polymethyl methacrylate (PMMA) matrices. The study first confirmed the quantum yield of each derivative and examined how the PMMA environment influences photoluminescence stability. Subsequently, each sample was exposed to a 447 nm laser for 1–2 hours to induce photo-degradation or photo-stability, after which the excitation was removed for intervals of 1 hour and 24 hours to evaluate recovery behavior. Photoluminescence (PL) spectra and FTIR measurements were analyzed to determine whether the PDIs return to their pristine state and how carbon chain length affects the rate and extent of recovery. It was confirmed that longer-chain PDIs (C5,C8) exhibited higher quantum yields, greater photostability, and faster recovery compared to shorter-chain analogues (C3). This work contributes to understanding reversible photobleaching and the structural factors that govern self-healing in organic semiconductor materials, offering valuable insights for the design of stable, efficient optoelectronic devices.

Advisor

Heungman Park

Subject Categories

Physical Sciences and Mathematics | Physics

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