Synthesis and Electronic Properties of Oxidized Benzo[1,2-b:4,5-b′]dithiophenes

19.5% Inverted organic photovoltaic with record long-lifetime via multifunctional interface engineering featuring radical scavenger

Advances in improving the operational lifetime of highly efficient organic photovoltaic (OPV) and understanding photo-degradation mechanisms in molecular level are currently limited, especially on the promising inverted OPV, posing critical challenges to commercialization. Here, we demonstrate a radical scavenger (3-(3,5-Di-tert-butyl-4-hydroxyphenyl)propionic acid) capped ZnO (BHT@ZnO) nanoparticles as the electron transport layer providing effective surface oxygen vacancy passivation and reactive radical capture capability. Encouragingly, this BHT@ZnO-based empowered device achieves a record inverted OPV efficiency of 19.47% (Certificated efficiency: 18.97%). The devices demonstrate light soaking-free behavior, long-term stability under ISOS-D-1 (94.2% PCE retention after 8904 h in ambient) and ISOS-L-1 testing protocol (81.5% PCE retention after 7724 h in MPP). More importantly, we elucidate detailed degradation mechanism in OPV involving selectively catalytic degradation of donor and acceptor by superoxide and hydroxyl radicals, respectively, as well as the degradation pathway of polymer donor upon radiation exposure. Performance enhancement and mechanism comprehension provide strong support for the development of OPV technology.

Serendipitous synthesis of phenanthrene derivatives by exploiting electrocyclization during thermolysis of Diels-Alder intermediate dihydrodibenzothiophene-S,S-dioxides

The Diels-Alder reaction of tetraaryl cyclopentadienones with benzo[b]thiophene-S,S-dioxides in nitrobenzene under reflux led to the formation of aryl/hetero-aryl fused phenanthrene derivatives via SO2 elimination of the intermediate dihydrodibenzothiophene-S,S-dioxides followed by 6π-electrocyclization and subsequent aromatization. The 6π-electrocyclization methodology was found to be applicable for assembling a wide variety of phenanthrene derivatives in good to moderate yields.

Recent Strategies to Develop Innovative Photosensitizers for Enhanced Photodynamic Therapy

This review presents a robust strategy to design photosensitizers (PSs) for various species. Photodynamic therapy (PDT) is a photochemical-based treatment approach that involves the use of light combined with a light-activated chemical, referred to as a PS. Attractively, PDT is one of the alternatives to conventional cancer treatment due to its noninvasive nature, high cure rates, and low side effects. PSs play an important factor in photoinduced reactive oxygen species (ROS) generation. Although the concept of photosensitizer-based photodynamic therapy has been widely adopted for clinical trials and bioimaging, until now, to our surprise, there has been no relevant review article on rational designs of organic PSs for PDT. Furthermore, most of published review articles in PDT focused on nanomaterials and nanotechnology based on traditional PSs. Therefore, this review aimed at reporting recent strategies to develop innovative organic photosensitizers for enhanced photodynamic therapy, with each example described in detail instead of providing only a general overview, as is typically done in previous reviews of PDT, to provide intuitive, vivid, and specific insights to the readers.

Efficient Near-Infrared Photosensitizer with Aggregation-Induced Emission for Imaging-Guided Photodynamic Therapy in Multiple Xenograft Tumor Models

Photodynamic therapy (PDT) strategy has been widely used in tumor treatment, and the reagents for reactive oxygen species (ROS) play a crucial role. Herein, we develop a fluorogen (TTB) containing an electron-accepting benzo[1,2-b:4,5-b']dithiophene 1,1,5,5-tetraoxide core and electron-donating 4,4'-(2,2-diphenylethene-1,1-diyl)bis(N,N-diphenylaniline) groups for image-guided targeting PDT application. TTB exhibits a prominent aggregation-induced emission (AIE) property with strong near-infrared (NIR) fluorescence in aggregates and is capable of efficiently generating ROS of O₂^•- and ¹O₂ under white light irradiation. The nanoparticles (RGD-4R-MPD/TTB NPs) with NIR emission (∼730 nm), high photostability, and low dark cytotoxicity are fabricated by encapsulating TTB within polymeric matrix and then modified with RGD-4R peptide. They show excellent performance in targeting PDT treatment of PC3, HeLa, and SKOV-3 cancer cells in vitro. The investigations on pharmacokinetics, biodistribution, and long-term tracing in vivo reveal that RGD-4R-MPD/TTB NPs can selectively accumulate in tumors for real-time, long-term image-guided PDT treatment. The RGD-4R-MPD/TTB NPs-mediated PDT in multiple xenograft tumor models disclose that the growth of cervical, prostate, and ovarian cancers in mice can be effectively inhibited. These results demonstrate that the reagents employing NIR fluorogen TTB as a photosensitizer could be promising candidates for in vivo image-guided PDT treatments of tumors.

Facile C–H iodination of electron deficient benzodithiophene-S,S-tetraoxide for the development of n-type polymers

A C–H iodination reaction of the electron-poor building block, benzo[1,2-b:4,5-b0]-dithiophene-1,1,5,5-tetraoxide has been reported. This facile functionalization has led to the development of two novel n-type donor–acceptor conjugated polymers.

Diels–Alder reaction of tetraarylcyclopentadienones with benzo[b]thiophene S,S-dioxides: an unprecedented de-oxygenation vs. sulfur dioxide extrusion

The Diels–Alder adduct, dihydrodibenzothiophene S,S-dioxides underwent aromatization either through de-oxygenation or extrusion of sulfur dioxide to furnish substituted dibenzothiophenes or benzenes.

Regioselective copper-catalyzed direct arylation of benzodithiophene-S,S-tetraoxide

An efficient copper-catalyzed direct arylation reaction for the regioselective functionalization of benzodithiophene-S,S-tetraoxide has been developed.