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Reducing aggregation caused quenching and enhancing stability is crucial in the fabrication of organic light-emitting diodes. Herein, we successfully fabricated blue-emitting coordination polymer glasses using perylene dye and a zinc-based coordination glass. The aggregation of perylene monomers in the solid state was significantly suppressed, and the hybrid glass demonstrated high stability and strong photoluminescent quantum yield (75.5%) under ambient conditions. [ABSTRACT FROM AUTHOR]

Lead-free organic–inorganic hybrid bismuth halides have been recognized as promising alternatives to lead-based perovskites for low-toxic and environmentally-friendly optoelectronic applications. These materials showcase unique optoelectronic properties, ascribed to their low-dimensional electronic structures, such as a long carrier lifetime, a strong quantum-well effect, self-trapped states, and good stability. However, there is still a lack of understanding of the structure dependency of these properties. Investigations of hybrid bismuth halides are thus highly urgent in the pursuit of developing functional optoelectronic devices utilizing these properties. Herein, we report a new one-dimensional (1D) polymeric organic–inorganic hybrid bismuth halide, PDABiI5 (PDA = 1,3-propane diammonium), which forms single crystals of centimeter size with a narrow optical bandgap of 1.77 eV. Interestingly, a reversible moisture-induced dimensional transformation was observed on 1D PDABiI5 through its conversion into 0D dimeric (PDA)2Bi2I10·2H2O, coming with a significant bandgap widening and photoluminescence shifts. This transformation is attributed to water molecules forming hydrogen bonds with the ammonium groups, promoting the deformation of Bi–I bonds from [BiI52−]n chains to edge-sharing [Bi2I10]4− dimers. This phenomenon presents exciting prospects for environmentally responsive device applications. Furthermore, optoelectronic characterizations demonstrated a long carrier lifetime exceeding 2 μs, a defect density of 1.49 × 1010 cm−3 and a high μτ product of 4.06 × 10−4 cm2 V−1. This work provides insights into the unique properties of PDABiI5 and (PDA)2Bi2I10·2H2O and their structure–property correlation, and offers promising avenues for the development of eco-friendly and functional optoelectronic devices. [ABSTRACT FROM AUTHOR]

Memristive devices such as resistive switching memories and artificial synapses have emerged as promising technologies to overcome the technological challenges associated with the von Neumann bottleneck. Recently, lead halide perovskites have drawn substantial research attention as the candidate material for memristors and artificial synapses due to their unique optoelectronic properties, solution processability, and mechanical flexibility. However, the toxicity of lead‐containing species has raised major concerns for health and the environment, which makes it crucial to transition from lead‐based to lead‐free materials for practical applications. Herein, the recent progress of lead‐free metal halides including perovskites and perovskite analogs for resistive memory and artificial synapse is reviewed. Initially, the fundamentals of lead‐free materials and switching mechanisms are introduced. Next, the material design, fabrication technique, and device performance are summarized and critically evaluated for each metal halide species. Finally, the challenges of the lead‐free metal halides toward memristors and artificial synapses are outlined and discussed, and some potential research directions for future study are proposed. [ABSTRACT FROM AUTHOR]

Organometal perovskite single crystals have been recognized as a promising platform for high‐performance optoelectronic devices, featuring high crystallinity and stability. However, a high trap density and structural nonuniformity at the surface have been major barriers to the progress of single crystal‐based optoelectronic devices. Here, the formation of a unique nanoisland structure is reported at the surface of the facet‐controlled cuboid MAPbI3 (MA = CH3NH3+) single crystals through a cation interdiffusion process enabled by energetically vaporized CsI. The interdiffusion of mobile ions between the bulk and the surface is triggered by thermally activated CsI vapor, which reconstructs the surface that is rich in MA and CsI with reduced dangling bonds. Simultaneously, an array of Cs‐Pb‐rich nanoislands is constructed on the surface of the MAPbI3 single crystals. This newly reconstructed nanoisland surface enhances the light absorbance over 50% and increases the charge carrier mobility from 56 to 93 cm2 V−1 s−1. As confirmed by Kelvin probe force microscopy, the nanoislands form a gradient band bending that prevents recombination of excess carriers, and thus, enhances lateral carrier transport properties. This unique engineering of the single crystal surface provides a pathway towards developing high‐quality perovskite single‐crystal surface for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Metal halide perovskites emerge as promising semiconductors for optoelectronic devices due to ease of fabrication, attractive photophysical properties, their low cost, highly tunable material properties, and high performance. High‐quality thin films of metal halide perovskites are the basis of most of these applications including solar cells, light‐emitting diodes, photodetectors, and electronic memristors. A typical fabrication method for perovskite thin films is the solution method, which has several limitations in device reproducibility, adverse environmental impact, and utilization of raw materials. Thermal evaporation holds great promise in addressing these bottlenecks in fabricating high‐quality halide perovskite thin films. It also has high compatibility with mass‐production platforms that are well‐established in industries. This review first introduces the basics of the thermal evaporation method with a particular focus on the critical parameters influencing the thin film deposition. The research progress of the fabrication of metal halide perovskite thin films is further summarized by different thermal evaporation approaches and their applications in solar cells and other optoelectronic devices. Finally, research challenges and future opportunities for both fundamental research and commercialization are discussed. [ABSTRACT FROM AUTHOR]

Recent years have witnessed much progress in both basic research and clinical trials regarding cancer immunotherapy with chimeric antigen receptor (CAR)-engineered T cells. The unique structure of CAR endows T cell tumor specific cytotoxicity and resistance to immunosuppressive microenvironment in cancers, which helps patients to better tackle the issue of immunological tolerance. Adoptive immunotherapy (AIT) using this supernatural T cell have gained momentum after decades of intense debates because of the promising results obtained from preclinical models and clinical trials. However, it is very important for us to evaluate thoroughly the challenges/obstacles before widespread clinical application, which clearly warrants more studies to improve our understanding of the mechanism underlying AIT. In this review, we focus on the critical issues related to the clinical outcomes of CAR-based adoptive immunotherapy and discuss the rationales to refine this new cancer therapeutic modality.

Background: Adoptive transfer of chimeric antigen receptor (CAR)-modified T cells appears to be a promising immunotherapeutic strategy. CAR combines the specificity of antibody and cytotoxicity of cytotoxic T lymphocytes, enhancing T cells' ability to specifically target antigens and to effectively kill cancer cells. Recent efforts have been made to integrate the costimulatory signals in the CAR to improve the antitumor efficacy. Epidermal growth factor receptor variant III (EGFRvIII) is an attractive therapeutic target as it frequently expresses in glioma and many other types of cancers. Our current study aimed to investigate the specific and efficient antitumor effect of T cells modified with CAR containing inducible costimulator (ICOS) signaling domain., Methods: A second generation of EGFRvIII/CAR was generated and it contained the EGFRvIII single chain variable fragment, ICOS signaling domain and CD3ζ chain. Lentiviral EGFRvIII/CAR was prepared and human CD3+ T cells were infected by lentivirus encoding EGFRvIII/CAR. The expression of EGFRvIII/CAR on CD3+ T cells was confirmed by flow cytometry and Western blot. The functions of EGFRvIII/CAR+ T cells were evaluated using in vitro and in vivo methods including cytotoxicity assay, cytokine release assay and xenograft tumor mouse model., Results: Chimeric EGFRvIIIscFv-ICOS-CD3ζ (EGFRvIII/CAR) was constructed and lentiviral EGFRvIII/CAR were made to titer of 106 TU/ml. The transduction efficiency of lentiviral EGFRvIII/CAR on T cells reached around 70% and expression of EGFRvIII/CAR protein was verified by immunoblotting as a band of about 57 kDa. Four hour 51Cr release assays demonstrated specific and efficient cytotoxicity of EGFRvIII/CAR+ T cells against EGFRvIII expressing U87 cells. A robust increase in the IFN-γ secretion was detected in the co-culture supernatant of the EGFRvIII/CAR+ T cells and the EGFRvIII expressing U87 cells. Intravenous and intratumor injection of EGFRvIII/CAR+ T cells inhibited the in vivo growth of the EGFRvIII expressing glioma cells., Conclusions: Our study demonstrates that the EGFRvIII/CAR-modified T cells can destroy glioma cells efficiently in an EGFRvIII specific manner and release IFN-γ in an antigen dependent manner. The specific recognition and effective killing activity of the EGFRvIII-directed T cells with ICOS signaling domain lays a foundation for us to employ such approach in future cancer treatment.

Osteosarcoma (OS) is one of the most common malignant bone tumors in early adolescence. Multi-drug chemotherapy has greatly increased the five year survival rate from 20% to 70%. However, the rate has been staggering for 30 years and the prognosis is particularly poor for patients with recurrence and metastasis. Our study aimed to investigate the role of Wnt-β-catenin, Notch and Hedgehog pathway in OS development because all these pathways are involved in skeletal development, tumorigenesis and chemoresistance. Our results showed that the major components in Wnt-β-catenin pathway, e.g. Wnt3a, β-catenin and Lef1, were consistently upregulated in human osteosarcoma cell line Saos2 cells compared to human fetal osteoblasts (hFOB), whereas the changes in the expression levels of Notch and Hh signaling molecules were not consistent. Knocking down β-catenin increased the Saos2 sensitivity to methotrexate (MTX) induced cell death. Consistently, the expression level of β-catenin protein correlated with the invasiveness of OS, as evidenced by more intensive β-catenin immunoreactivity in higher grade OS samples. Chemical inhibition of the Wnt-β-catenin signaling enhanced MTX mediated death of Saos2 cells. A synergistic effect with MTX was observed when both inhibitors for Wnt-β-catenin and Notch pathways were simultaneously used, while the addition of the Hh inhibitor did not further improve the efficacy. Our findings provide some novel insight to OS pathogenesis and lay a foundation for future application of Wnt-β-catenin and Notch inhibitors together with the currently used chemotherapeutic drugs to improve the outcome of OS treatment., (Published by Elsevier Inc.)