Isoindigo-Based Dual-Acceptor Conjugated Polymers Incorporated Conjugation Length and Intramolecular Charge Transfer for High-Efficient Photothermal Conversion

Anisole Processible n-Type Conjugated Polymers Synthesized via C─H/C─H Oxidative Direct Arylation Polycondensation for Organic Electrochemical Transistors

The development of n-type polymers for organic electrochemical transistors (OECTs) has lagged significantly behind their p-type counterparts. Moreover, these polymers are often synthesized via Stille polycondensation. Herein, three polymers with thiazole-flanked diketopyrrolopyrrole is synthesized as the monomer through C─H/C─H oxidative direct arylation polycondensation (Oxi-DArP). This protocol employs unfunctionalized (C─H terminated) monomers, and the generated byproducts are environmentally benign. The electron-deficient polymer backbone confers these polymers with LUMO energy levels below -4.20 eV, enabling all of them to exhibit n-type behavior in OECTs. Additionally, the resulting polymers are soluble in the green solvent anisole. With an optimized alkyl spacer between oligo(ethylene glycol) side chain and conjugated backbone, the polymer gTzDPP-C8 showed the best device performance with geometry normalized transconductance (gm,norm) up to 6.31 S cm-1 and µC* up to 23.1 F V-1 cm-1 s-1. This work has successfully proved that C─H/C─H Oxi-DArP is a promising method for synthesizing n-type OMIECs to fulfill high-performance OECTs.

Near-Infrared Absorbing Para-Azaquinodimethane Conjugated Polymers Synthesized via the Transition-Metal-Free Route toward Efficient Photothermal Conversion

Conjugated polymers with strong absorption in the second near-infrared (NIR-II) window have multiple applications. However, the development of new type of NIR-II conjugated polymers via facile and green methods remains challenging. Herein, this work reports a mild and convenient transition-metal-free method to synthesize near-infrared absorbing quinoidal conjugated polymers containing para-azaquinodimethane (AQM) moieties. The AQM quinoidal conjugated polymers with unique molecular structures and tunable optoelectronic properties can be synthesized by combining the Knoevenagel polycondensation of aromatic dialdehyde monomers with commercially available 1,4-diacetyl-2,5-piperazinedione and the following alkylation reaction. The resultant polymer PQ-DPP shows remarkable NIR-II absorption with a narrow band gap of about 1.08 eV. PQ-DPP nanoparticles exhibit high photothermal conversion efficiency of up to 48% under 1064 nm laser irradiation (1 W cm-2) endowing this polymer with potential in bio-related applications.

Semiconducting Polymers for Cancer Immunotherapy

As a monumental breakthrough in cancer treatment, immunotherapy has attracted tremendous attention in recent years. However, one challenge faced by immunotherapy is the low response rate and the immune-related adverse events (irAEs). Therefore, it is important to explore new therapeutic strategies and platforms for boosting therapeutic benefits and decreasing the side effects of immunotherapy. In recent years, semiconducting polymer (SP), a category of organic materials with π-conjugated aromatic backbone, has been attracting considerable attention because of their outstanding characteristics such as excellent photophysical features, good biosafety, adjustable chemical flexibility, easy fabrication, and high stability. With these distinct advantages, SP is extensively explored for bioimaging and photo- or ultrasound-activated tumor therapy. Here, the recent advancements in SP-based nanomedicines are summarized for enhanced tumor immunotherapy. According to the photophysical properties of SPs, the cancer immunotherapies enabled by SPs with the photothermal, photodynamic, or sonodynamic functions are highlighted in detail, with a particular focus on the construction of combination immunotherapy and activatable nanoplatforms to maximize the benefits of cancer immunotherapy. Herein, new guidance and comprehensive insights are provided for the design of SPs with desired photophysical properties to realize maximized effectiveness of required biomedical applications.