Design of BODIPY dyes as triplet photosensitizers: electronic properties tailored for solar energy conversion, photoredox catalysis and photodynamic therapy

Abstract

BODIPYs offer a versatile platform to build organic triplet photosensitisers for PDT, TTA upconversion and photocatalysis. Tuning their properties provides the opportunity of replacing heavy-metal complexes and can lead to improved sustainability.

Application of time-resolved electron paramagnetic resonance spectroscopy in the mechanistic study of thermally activated delayed fluorescence (TADF) materials

“…17,20,54 In this case, the 1 CT -3 LE may be enhanced by spin orbit charge transfer ISC (SOCT-ISC). 37,[55][56][57][58] With the purpose of design of heavy atomfree triplet photosensitizers based on the electron donor-acceptor molecular structure, the orthogonal geometry is beneficial for the SOCT-ISC. 37,56,57,59 This is also applicable to TADF emitters.…”

“…the SOCT-ISC mechanism. 37,[56][57][58] Since the T 1 state of the native NI moiety is ca. 2.29 eV, 68 we expect TADF only for NI-N-PTZ.…”

EGFR-Targeted Photodynamic Therapy

“…The PS in the S 1 excited state is unstable, with a lifetime in the range of ns, resulting in decay to the ground state S 0 through a (i) radiative (fluorescence) or (ii) non-radiative (energy dissipation as heat) relaxation process (Figure 1). A third pathway may occur when the singlet−triplet energy gap is sufficiently small: an intersystem crossing (ISC) from S 1 to T 1 [13,14]. The T 1 excited state is generally characterized by a long lifetime (from µs to s) and can be subjected to different photophysical and photochemical processes, such as (i) phosphorescent emission and (ii) generation of reactive oxygen species (ROS).…”

Development of Geometry-Controlled All-Orthogonal BODIPY Trimers for Photodynamic Therapy and Phototheragnosis

“…CT states can mediate the triplet state population, promoting singlet oxygen generation by energy transfer (type II mechanism of ROS photogeneration), 10c , 17 as supported by the detection of the 1 O 2 phosphorescence at 1270 nm (see the experimental details in the Supporting Information ). The most accepted mechanism, enabling the triplet state to be reached from the populated CT one, is spin–orbit charge transfer intersystem crossing (SOCT-ISC).…”