Chemistry - An Asian Journal, Journal Year: 2024, Volume and Issue: unknown
Published: Dec. 30, 2024
Abstract Visible‐light absorbing metal‐free organic dyes are of increasing demand for various optoelectronic applications because their great structure‐function tunability through chemical means. Several also show huge potential in triplet photosensitization, generating reactive singlet oxygen. Understanding the structure‐property relationships many well‐known fluorescein is paramount importance designing next‐generation energy efficient dyes, which currently limited. For example, role heavy atoms excited‐state deactivations not fully understood these dyes. Herein, 9 halogenated (Cl, Br, I) with varied halogen concentrations and positions studied using time‐dependent range‐separated hybrid combined polarizable continuum model water dielectric accounting polarization screening effects. Excited state energies via radiative non‐radiative pathways well described 0–0 corrected excitation energies. Calculated results reasonable agreement available experimental data. However, no systematic correlation found between heavy‐atom effect calculated intersystem crossing/fluorescence rates. Not surprisingly, to be more pronounced iodinated compared brominated analogues. Halogen position plays a critical determining deactivation All similar fluorescence rates ~10 8 . Whereas, crossing much smaller vary from 2 10 4 Nevertheless, lower quantum yields some attributed large internal conversion. Microscopic understanding on properties several reported here will aid developing advanced dye based photosensitizers emitters.
Language: Английский