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Heavy‐Atom‐Free Bay‐Substituted Perylene Diimide Donor‐Acceptor Photosensitizers
Author(s) -
Deckers Jasper,
Cardeynaels Tom,
Lutsen Laurence,
Champagne Benoît,
Maes Wouter
Publication year - 2021
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202100269
Subject(s) - intersystem crossing , photochemistry , diimide , perylene , acceptor , chemistry , triphenylamine , density functional theory , photoexcitation , electron donor , intramolecular force , singlet state , materials science , excited state , computational chemistry , molecule , stereochemistry , organic chemistry , physics , condensed matter physics , catalysis , nuclear physics
Perylene diimide (PDI) dyes are extensively investigated because of their favorable photophysical characteristics for a wide range of organic material applications. Fine‐tuning of the optoelectronic properties is readily achieved by functionalization of the electron‐deficient PDI scaffold. Here, we present four new donor‐acceptor type dyads, wherein the electron donor units – benzo[1,2‐ b : 4,5‐ b’ ]dithiophene, 9,9‐dimethyl‐9,10‐dihydroacridine, dithieno[3,2‐ b : 2’,3’‐ d ]pyrrole, and triphenylamine‐are attached to the bay‐positions of the PDI acceptor. Intersystem crossing occurs for these systems upon photoexcitation, without the aid of heavy atoms, resulting in singlet oxygen quantum yields up to 80 % in toluene solution. Furthermore, this feature is retained when the system is directly irradiated with energy corresponding to the intramolecular charge‐transfer absorption band (at 639 nm). Geometrical optimization and (time‐dependent) density functional theory calculations afford more insights into the requirements for intersystem crossing such as spin‐orbit coupling, dihedral angles, the involvement of charge‐transfer states, and energy level alignment.