Inhibiting Interfacial Nonradiative Recombination in Inverted Perovskite Solar Cells with a Multifunctional Molecule.

Interface-induced nonradiative recombination losses at the perovskite/electron transport layer (ETL) are an impediment to improving the efficiency and stability of inverted (p-i-n) perovskite solar cells (PSCs). Tridecafluorohexane-1-sulfonic acid potassium (TFHSP) is employed as a multifunctional dipole molecule to modify the perovskite surface. The solid coordination and hydrogen bonding efficiently passivate the surface defects, thereby reducing nonradiative recombination. The induced positive dipole layer between the perovskite and ETLs improves the energy band alignment, enhancing interface charge extraction. Additionally, the strong interaction between TFHSP and the perovskite stabilizes the perovskite surface, while the hydrophobic fluorinated moieties prevent the ingress of water and oxygen, enhancing the device stability. The resultant devices achieve a power conversion efficiency (PCE) of 24.6%. The unencapsulated devices retain 91% of their initial efficiency after 1000 h in air with 60% relative humidity, and 95% after 500 h under maximum power point (MPP) tracking at 35 °C. The utilization of multifunctional dipole molecules opens new avenues for high-performance and long-term stable perovskite devices.

Polyoxometalate-based frameworks for photocatalysis and photothermal catalysis.

Polyoxometalate-based frameworks (POM-based frameworks) are extended structures assembled from metal-oxide cluster units and organic frameworks that simultaneously possess the virtues of POMs and frameworks. They have been attracting immense attention because of their diverse architectures and charming topologies and also due to their probable application prospects in the areas of catalysis, separation, and energy storage. In this review, the recent progress in POM-based frameworks including POM-based metal organic frameworks (PMOFs), POM-based covalent organic frameworks (PCOFs), and POM-based supramolecular frameworks (PSFs) is systematically summarized. The design and construction of a POM-based framework and its application in photocatalysis and photothermal catalysis are introduced, respectively. Finally, our brief outlooks on the current challenges and future development of POM-based frameworks for photocatalysis and photothermal catalysis are provided.

Synchronously boosting type-I photodynamic and photothermal efficacies via molecular manipulation for pancreatic cancer theranostics in the NIR-II window.

In view of the fact that pancreatic cancer, called as the king of cancer, is one of the most lethal malignancies, exploring effective technologies for pancreatic cancer diagnosis and therapy remains an appealing yet significantly challenging task. Phototheranostics has recently received considerable attention by virtue of its various distinctive advantages. However, the limited penetration depth, strong oxygen-dependence and high heat shock protein-inhibition of conventional phototheranostic materials severely hamper their overall theranostic efficacy, especially for deep-seated hypoxia tumors, such as pancreatic tumor. In this study, an aggregation-induced emission (AIE)-featured photosensitizer, namely DCTBT, synchronously sharing NIR-II fluorescence imaging (FLI), diminished oxygen-dependent type-I photodynamic therapy (PDT) and high-efficiency photothermal therapy (PTT) functions was subtly constructed by molecular engineering. With the aid of an EGFR-targeting-peptide-modified amphiphilic polymer, the as-prepared DCTBT-loaded liposomes is capable of effectively accumulating at and visualizing pancreatic tumor, as well as significantly suppressing the tumor growth on both subcutaneous and orthotopic PANC-1 tumor mice models. This study thus brings useful insights into designing the next generation of cancer theranostic agents for potential clinical applications.

Unveiling the crucial contributions of electrostatic and dispersion interactions to the ultralong room-temperature phosphorescence of H-bond crosslinked poly(vinyl alcohol) films.

Organic phosphors exhibiting room-temperature phosphorescence (RTP) in the amorphous phase are promising candidates for optoelectronic and biomedical applications. In particular, noncovalently embedding organic phosphors into a poly(vinyl alcohol) (PVA) matrix has emerged as the most commonly used yet effective approach to obtain amorphous organic RTP materials. While the role of intermolecular hydrogen-bonding interactions in determining the RTP properties of doping PVA systems has been well documented, we show that electrostatic and dispersion interactions contribute crucially to the ultralong RTP properties of doping PVA films. This impressive outcome reveals the nature of non-covalent interactions existing in doping PVA systems for the first time. We demonstrate this through detailed experimental and computational studies for a series of hydrogen-bond crosslinked PVA films where star-shaped organic phosphors containing active groups of carboxy, hydroxy, and amino act as multisite crosslinkers for the construction of extensive hydrogen-bonding networks. More importantly, we successfully obtain an ultralong RTP lifetime of up to 1.74 s by tuning the electrostatic and dispersion interactions between organic phosphors and the PVA matrix through simply modifying active groups of organic phosphors. This instructive work will provide new guiding principles for the exploration of amorphous organic RTP systems.

Good Steel Used in the Blade: Well-Tailored Type-I Photosensitizers with Aggregation-Induced Emission Characteristics for Precise Nuclear Targeting Photodynamic Therapy.

Photodynamic therapy (PDT) has long been recognized to be a promising approach for cancer treatment. However, the high oxygen dependency of conventional PDT dramatically impairs its overall therapeutic efficacy, especially in hypoxic solid tumors. Exploration of distinctive PDT strategy involving both high-performance less-oxygen-dependent photosensitizers (PSs) and prominent drug delivery system is an appealing yet significantly challenging task. Herein, a precise nuclear targeting PDT protocol based on type-I PSs with aggregation-induced emission (AIE) characteristics is fabricated for the first time. Of the two synthesized AIE PSs, TTFMN is demonstrated to exhibit superior AIE property and stronger type-I reactive oxygen species (ROS) generation efficiency owing to the introduction of tetraphenylethylene and smaller singlet-triplet energy gap, respectively. With the aid of a lysosomal acid-activated TAT-peptide-modified amphiphilic polymer poly(lactic acid)12k-poly(ethylene glycol)5k-succinic anhydride-modified TAT, the corresponding TTFMN-loaded nanoparticles accompanied with acid-triggered nuclear targeting peculiarity can quickly accumulate in the tumor site, effectively generate type-I ROS in the nuclear region and significantly suppress the tumor growth under white light irradiation with minimized systematic toxicity. This delicate "Good Steel Used in the Blade" tactic significantly maximizes the PDT efficacy and offers a conceptual while practical paradigm for optimized cancer treatment in further translational medicine.

Fluorine-substituted quinoidal thiophene with a F-H hydrogen bond locked conformation for high-performance n-channel organic transistors.

The novel dicyanomethylene-substituted 1,2-bis(thieno[3,2-b]thiophene-2-yl)ethene based quinoidal compounds QBTTE and F2-QBTTE are reported. The FH (vinylene) hydrogen bonds lock the backbone conformation and greatly improve the transistor performance of F2-QBTTE.

Cu-Thienoquinone Charge-Transfer Complex: Synthesis, Characterization, and Application in Organic Transistors.

A facile and unusual reaction between thienoquinone compound QDTBDT2C and copper is reported. The formation of Cu-QDTBDT2C complex is proved by absorption spectra, IR spectra, Raman spectra, and X-ray photoelectron spectroscopy data. This complex can serve as a doping layer at the interface of Cu/QDTBDT2C and greatly improve the performance of organic transistors in which the copper electrode is source/drain electrodes and QDTBDT2C is an active layer. The transistors display an electron mobility of 0.95 cm2 V-1 s-1, to our knowledge, the highest electron mobility reported for copper electrode-based n-type transistors and nearly two times higher than that of the Au electrode-based devices. These results demonstrate the potential applications of Cu-QDTBDT2C complex in organic electronics, and the unique properties of QDTBDT2C (spontaneously reacting with copper) provide a new insight into the design of n-type organic semiconductors for copper electrode-based organic transistors.

Modulating Surface Morphology and Thin-Film Transistor Performance of Bi-thieno[3,4-c]pyrrole-4,6-dione-Based Polymer Semiconductor by Altering Preaggregation in Solution.

Due to their strong intermolecular interactions, polymer semiconductors aggregate in solution even at elevated temperature. With the aim to study the effect of this kind preaggregation on the order of thin films and further transistor performance, bi-thieno[3,4-c]pyrrole-4,6-dione and fluorinated oligothiophene copolymerized polymer semiconductor P1, which shows strong temperature-dependent aggregation behavior in solution, is synthesized. Its films are deposited through a temperature-controlled dip-coating technique. X-ray diffraction and atomic force microscopy results reveal that the aggregation behavior of P1 in solution affects the microstructures and order of P1 films. The charge transport properties of P1 films are investigated with bottom-gate top-contacted thin-film transistors. The variation of device performance (from 0.014  to 1.03 cm2 V-1 s-1) demonstrates the importance of optimizing preaggregation degree. The correlation between preaggregation degree and transistor performance of P1 films is explored.

Bithienopyrroledione vs. thienopyrroledione based copolymers: dramatic increase of power conversion efficiency in bulk heterojunction solar cells.

Bithienopyrroledione (bi-TPD) based polymers P1 and P2 are designed and synthesized. Photovoltaic devices based on P1:PC71BM and P2:PC71BM blend films show power conversion efficiencies (PCEs) of 8.22% and 9.08%, respectively, whereas devices based on their thienopyrroledione (TPD)-based analogue P3 and PC71BM blend films display a PCE of 5.10%.

Diacenaphthylene-fused benzo[1,2-b:4,5-b']dithiophenes: polycyclic heteroacenes containing full-carbon five-membered aromatic rings.

We herein report on an efficient synthesis of diacenaphthylene-fused benzo[1,2-b:4,5-b']dithiophenes and demonstrate that their packing structure in the solid state depends on the substituent groups. These compounds form dimers with their radical cations in high concentration solution and exhibit good field-effect mobility.

A Furan-Thiophene-Based Quinoidal Compound: A New Class of Solution-Processable High-Performance n-Type Organic Semiconductor.

The furan-thiophene-based quinoidal organic semiconductor, TFT-CN, is designed and synthesized. TFT-CN displays a high electron mobility of 7.7 cm(2) V(-1) s(-1) , two orders of magnitude higher than the corresponding thiophene-based derivative.

Syntheses and properties of nine-ring-fused linear thienoacenes.

π-Extended nine-ring-fused linear thienoacenes 1a­c with internal thieno[3,2-b;4,5-b']dithiophene substructures were synthesized. Their optical and electrochemical properties were investigated. Thin-film transistor characteristics showed all compounds displayed high device reproducibility and nearly no dependence on substrate temperatures. The highest performance was observed for 1c-based devices with mobility up to 1.0 cm2/Vs and current on/off ratio of 10(7), whereas the maximum mobility was 0.5 cm2/Vs for 1b and 0.011 cm2/Vs for 1a.