Acceptor-acceptor-type conjugated polymer semiconductors

The rapid development of electronic devices such as organic field-effect transistors(OFETs)and solar cells makes the research and development of electronic transport materials imminent.The acceptor-acceptortype(AàA-type)conjugated n-type polymer semiconductors have caught much attention due to the outstanding advantages on excellent electron-accepting capabilities,the precise adjustment of energy levels and the mass production at low fabrication cost.This article systematically reviews the polymerization methods of AàA-type polymers and the recent advancements applied in OFETs and polymer solar cells(PSCs).The analyses of the synthesis and the relationship between device performances and polymer molecular structures may provide a constructive guidance for the further development of highperformance n-type polymer materials.

Combination of S…N and S…Cl Noncovalently Conformational Locks for Constructing High-Planarity and Low-Cost Nonfused-Ring Electron Acceptors

Comprehensive Summary By employing thiazole and 4-chlorothiazole as the A′units,two A-D-A′-D-A type nonfused-ring electron acceptors(NFREAs)Tz-H and Tz-Cl were designed and synthesized.Replacing thiazole in Tz-H with 4-chlorothiazole can not only remarkably shorten the synthetic route through C—H direct arylation but also enhance molecular planarity with the simultaneous incorporation of S…N and S…Cl noncovalently conformational locks(NoCLs).The photovoltaic devices based on PM6:Tz-Cl exhibited a power conversion efficiency as high as 11.10%,much higher than that of PM6:Tz-H(6.41%),mainly due to more efficient exciton dissociation,better and more balanced carrier mobility,less charge recombination,and more favorable morphology.These findings demonstrate the great potential of NoCLs in achieving low-cost and high-performance NFREAs.

White-light-driven fluorescence switch for super-resolution imaging guided photodynamic and photoacid therapy

Photocaged fluorophores with photoactivatable characteristics presented important applications in imaging the biological structures and processes.Taking advantage of their super-resolution imaging merits to manipulate and visualize anti-cancer treatment is always a goal of modern clinical medicine.Traditional photodynamic therapy(PDT) is a noninvasive treatment but limited in intracellular oxygen content.Type I PDT and photoacid therapy(PAT) are two effective supplements of traditional PDT especially in hypoxic condition.Herein,a novel white-light-driven fluorescence switch(7H-dibenzo[c,g]carbazol-7-yl)(2-iodophenyl)methanone(2IB) was designed and synthesized as an unprecedent “all in one” platform for stochastic optical reconstruction microscopy(STORM) imaging guided Type Ⅰ/Ⅱ PDT and PAT.The experimental and theoretical studies revealed that the working mechanism is based on two competing paths under excitation:photosensitization and photocyclization reaction.Efficient intersystem crossing(ISC) ensured the generation of reactive oxygen species(ROS) for PDT,while low energy barrier facilitated the photocyclization reaction that simultaneously yielded emissive fluorophores(2IBC) and H^(+) for super-resolution imaging and photoacid,respectively.Impressively,the fluorescent intensity of mitochondria-targeted 2IBC was positively correlated with treatment efficacy,which is beneficial to spatiotemporally visualized therapeutic process and outcome.As a result,superior anti-tumor performance was achieved in vitro and in vivo.This contribution provided a multifunctional nanodrug paradigm for multimode cancer diagnosis and treatment.