Regioisomeric Control of Charge Transport Properties in Fluoranthene-Fused 12-Ring Heteroarenes.

Heteroarene-based organic semiconductors (OSCs) have emerged as promising material candidates for large-area, flexible electronic and photonic devices due to their favorable π-conjugation systems and tunable optoelectronic properties. However, their development is still hindered by synthetic and design challenges, in particular, the limited access to highly polycyclic heteroarenes with tunable properties and the unexplored effects of topological isomerism. Here, we have successfully synthesized three regioisomeric thienoacenes (-) by fusing a dicyanofluoranthene unit, which have an identical 12-fused ring composition but different molecular topologies with [a] or [c]-fusion and syn or anti-CN substitution.

Initiation-Confined Holographic Photopolymerization under Visible Light.

Holographic photopolymerization provides a robust approach for the advanced manufacturing of structurally ordered devices. However, photogenerated radicals in bright regions are prone to cross-regional diffusion and induce unwanted polymerizations in dark regions, making efficient holographic manufacturing exceedingly challenging. Herein, we report a breakthrough by spatially confining the initiation function, enabling the unprecedentedly rapid formation of predesigned submicron-ordered grating structures within merely 0.

Synergistic Solvent and Composition Engineering of Perovskites for Tandems on Industrial Silicon.

Wide-bandgap perovskites based on mixed formamidinium-cesium cation and iodide-bromide halide are promising materials in the top cells that are well-matched with crystalline silicon bottom cells to construct efficient tandem photovoltaics. Nevertheless, mixed cation-halide perovskite films with submicron film thickness suffer from poor crystallinity with inhomogeneous and undesirable phases, owing to the presence of multiple pathways of crystal nucleation and phase transition. Herein, we propose a synergistic solvent and composition engineering (SSCE) strategy to regulate the solvated phases and manipulate the transition pathways simultaneously.

Tuning the Near-Infrared Aggregate of a Multicationic Photosensitizer through Molecular Coassembly for Symbiotic Photothermal Therapy and Chemotherapy.

Cationic photosensitizers (PSs) offer many intriguing advantages, in addition to generating heat or reactive oxygen species for cancer phototherapy. However, the preparation of cationic PSs with enhanced near-infrared (NIR) absorption remains a significant challenge. In this work, we have synthesized a PS TPBBT, which incorporates a strong electron-withdrawing unit, benzobisthiadiazole, and four terminal pyridinium groups.

High-Security Plastic with Integrated Holographic and Phosphorescent Images.

Organic room temperature phosphorescence (ORTP) polymer materials have sparked considerable research interests in recent years, but their optical function is still limited for multi-mode optical imaging. Herein, a feasible and universal approach is proposed to endow ORTP polymer materials with periodic refractive index modulation functions by holographic patterning. The key to this approach is to design a two-stage stepwise crosslinking.

Aggregation control of anionic pentamethine cyanine enabling excitation wavelength selective NIR-II fluorescence imaging-guided photodynamic therapy.

Near-infrared (NIR)-II fluorescence imaging-guided photodynamic therapy (PDT) has shown great potential for precise diagnosis and treatment of tumors in deep tissues; however, its performance is severely limited by the undesired aggregation of photosensitizers and the competitive relationship between fluorescence emission and reactive oxygen species (ROS) generation. Herein, we report an example of an anionic pentamethine cyanine (C5T) photosensitizer for high-performance NIR-II fluorescence imaging-guided PDT. Through the counterion engineering approach, a triphenylphosphine cation (Pco) modified with oligoethylene glycol chain is synthesized and adopted as the counterion of C5T, which can effectively suppress the excessive and disordered aggregation of the resulting C5T-Pco by optimizing the dye amphipathicity and enhancing the cyanine-counterion interactions.

Fluoranthene imide dimers with strong isomeric effects on the charge transport properties.

To date, the development of high-performance n-type organic semiconductors has remained challenging due to the scarcity of highly electron-deficient π-conjugated structural units and the difficulty of controlling intermolecular packing in the thin-film state. In addition, there have been few reports on the use of dimer design to tune the optoelectronic properties of materials. Herein, we report new cyano-substituted fluoranthene imide-based dimers (F16 and F17) for small-molecule n-type organic semiconductors.

Enhancing Efficiency and Stability of Inverted Perovskite Solar Cells through Solution-Processed and Structurally Ordered Fullerene.

The electron transporting layer (ETL) used in high performance inverted perovskite solar cells (PSCs) is typically composed of C, which requires time-consuming and costly thermal evaporation deposition, posing a significant challenge for large-scale production. To address this challenge, herein, we present a novel design of solution-processible electron transporting material (ETM) by grafting a non-fullerene acceptor fragment onto C. The synthesized BTPC exhibits an exceptional solution processability and well-organized molecular stacking pattern, enabling the formation of uniform and structurally ordered film with high electron mobility.

Supramolecular H-Aggregates of Squaraines with Enhanced Type I Photosensitization for Combined Photodynamic and Photothermal Therapy.

Combined photodynamic and photothermal therapy (PDT and PTT) can achieve more superior therapeutic effects than the sole mode by maximizing the photon utilization, but there remains a significant challenge in the development of related single-molecule photosensitizers (PSs), particularly those with type I photosensitization. In this study, self-assembly of squaraine dyes (SQs) is shown to be a promising strategy for designing PSs for combined type I PDT and PTT, and a supramolecular PS (TPE-SQ7) has been successfully developed through subtle molecular design of an indolenine SQ, which can self-assemble into highly ordered H-aggregates in aqueous solution as well as nanoparticles (NPs). In contrast to the typical quenching effect of H-aggregates on reactive oxygen species (ROS) generation, our results encouragingly manifest that H-aggregates can enhance type I ROS (OH) generation by facilitating the intersystem crossing process while maintaining a high PTT performance.

Charge Management Enables Efficient Spontaneous Chromatic Adaptation Bipolar Photodetector.

Solution-processed photodetectors have emerged as promising candidates for next-generation of visible-near infrared (vis-NIR) photodetectors. This is attributed to their ease of processing, compatibility with flexible substrates, and the ability to tune their detection properties by integrating complementary photoresponsive semiconductors. However, the limited performance continues to hinder their further development, primarily influenced by the difference of charge transport properties between perovskite and organic semiconductors.

Green-solvent Processable Dopant-free Hole Transporting Materials for Inverted Perovskite Solar Cells.

The commercialization of perovskite solar cells (PVSCs) urgently requires the development of green-solvent processable dopant-free hole transporting materials (HTMs). However, strong intermolecular interactions that ensure high hole mobility always compromise the solubility and film-forming ability in green solvents. Herein, we show a simple but effective design strategy to solve this trade-off, that is, constructing star-shaped D-A-D structure.

Recent advances in developing high-performance organic hole transporting materials for inverted perovskite solar cells.

Inverted perovskite solar cells (PVSCs) have recently made exciting progress, showing high power conversion efficiencies (PCEs) of 25% in single-junction devices and 30.5% in silicon/perovskite tandem devices. The hole transporting material (HTM) in an inverted PVSC plays an important role in determining the device performance, since it not only extracts/transports holes but also affects the growth and crystallization of perovskite film.

Backbone Engineering Enables Highly Efficient Polymer Hole-Transporting Materials for Inverted Perovskite Solar Cells.

The interface and crystallinity of perovskite films play a decisive role in determining the device performance, which is significantly influenced by the bottom hole-transporting material (HTM) of inverted perovskite solar cells (PVSCs). Herein, a simple design strategy of polymer HTMs is reported, which can modulate the wettability and promote the anchoring by introducing pyridine units into the polyarylamine backbone, so as to realize efficient and stable inverted PVSCs. The HTM properties can be effectively modified by varying the linkage sites of pyridine units, and 3,5-linked PTAA-P1 particularly demonstrates a more regulated molecular configuration for interacting with perovskites, leading to highly crystalline perovskite films with uniform back contact and reduced defect density.

Hypercrosslinking porous polymer layers on TiO-graphene photocatalyst: Enhanced adsorption of water pollutants for efficient degradation.

Solar-driven photocatalysis offers an environmentally friendly and sustainable approach for the degradation of organic pollutants in water without chemical additives, but the low specific surface area and adsorption capacity of common photocatalysts restricts the surface reactions with the contaminants. Herein, we hypercrosslinked polymer layers on TiO-graphene surface to enlarge the specific surface area from 136 to 988 m/g, leading to a high adsorption capacity of sulfadiazine as 54.3 mg/g, which is 15.

Morphological Transformation and In Situ Polymerization of Caspase-3 Responsive Diacetylene-Containing Lipidated Peptide Amphiphile for Self-Amplified Cooperative Antitumor Therapy.

In order to artificially regulate cell behaviors, intracellular polymerization as an emerging chemical technique has attracted much attention. Yet, it is still a challenge to achieve effective intracellular polymerization to conquer tumors in the complex cellular environment. Herein, this work develops a tumor-targeting and caspase-3 responsive nanoparticle composed of a diacetylene-containing lipidated peptide amphiphile and mitochondria-targeting photosensitizer (C3), which undergoes nanoparticle-to-nanofiber transformation and efficient in situ polymerization triggered by photodynamic treatment and activation of caspase-3.

Molecular Insights of Non-fused Ring Acceptors for High-Performance Non-fullerene Organic Solar Cells.

Non-fullerene acceptors with fused-ring structures have rapidly improved the performance of organic solar cells over the past five years, but they still suffer from synthetic complexity and thus high material costs, one of the major obstacles of hindering their commercialization process. The construction of non-fused ring acceptors (NFRAs) has recently been regarded as a feasible solution due to their facile synthesis and satisfactory device performances. Thus in this concept, we highlight the important progress of NFRAs in recent years, and discuss the key relationship between molecular design strategies and device performance.

On the interface reactions and stability of nonfullerene organic solar cells.

Long-term stability is critical for organic solar cells (OSCs) for practical applications. Several factors affect the stability of OSCs, including materials stability, morphology stability of bulk-heterojunctions and interface stability. In this perspective, we focus on interface stability due to interfacial reactions between the emerging acceptor-donor-acceptor (A-D-A) type nonfullerene active layers and interfacial layers.

A New Diazabenzo[k]fluoranthene-Based D-A Conjugated Polymer Donor for Efficient Organic Solar Cells.

The development of wide-bandgap polymer donors having complementary absorption and compatible energy levels with near-infrared (NIR) absorbing nonfullerene acceptors is highly important for realizing high-performance organic solar cells (OSCs). Herein, a new thiophene-fused diazabenzo[k]fluoranthene derivative is successfully synthesized as the electron-deficient unit to construct an efficient donor-acceptor (D-A) type alternating copolymer donor, namely, PABF-Cl, using the chlorinated benzo[1,2-b:4,5-b']dithiophene as the copolymerization unit. PABF-Cl exhibits a wide optical bandgap of 1.