halide perovskites (LDHPs), the optically active inorganic blocks are separated and surrounded by insulating organic components with intrinsic quantum confinement effects, which readily leads to firmly confined bound excitons in the metal halide species under photo excitation. Simultaneously, the strong electronquantum coupling transiently localizes the excitons along with excited-state structural deformation, which produces selftrapped excitons (STE) with lower excited state energy. [4] Therefore, the bulk LDHPs always display strongly Stokes-shifted broadband light emissions, which are different from the narrow emission bands of 3D halide perovskites. [5] These distinctive luminescent performances endow LDHPs with a series of unique applications complementary to the 3D perovskites in solid-state lighting, X-ray scintillation, remote thermometry, and thermography, especially for white light emitting diodes (WLEDs). [6] Among all the PL qualities, PL quantum yield (PLQY) is one of the most important indicators for optoelectronic applications of hybrid halide perovskites. To achieve higher PLQY and more desirable luminescence performance, substantial optically active centers based on ns 2 electronic configuration of valence shell have been explored including Sn 2+ , Ge 2+ , Pb 2+ , Bi 3+ , and Sb 3+ . [7][8][9] In these fascinating hybrid metal halides, the 5s 2 metal halides readily occupy the maximum of emission efficiency owing to the unique expressed structural distortion level induced by the out shell lone pair. [10] Simultaneously considering the instabilities of Sn 2+ and Ge 2+ halides, toxicity of Pb 2+ , metal as well as low efficiencies of Bi 3+ phases, green 5s 2 Sb 3+ based hybrid metal halides are deemed to be one of most promising ultrabroadband luminescent materials with higher PLQYs and oxidation resistance abilities. [7b,8a,11] Up to now, the PLQYs of 0D hybrid antimony halides based on discrete [SbX 5 ] 2− and [SbX 6 ] 3− units can reach up to near unity due to strong quantum confinement effect. [12] These outstanding PL properties intrigued further in-depth understanding the enhancement or modulating mechanism of PLQY for hybrid antimony halides from molecular design level, which is also greatly desirable for subsequent rational design of new high-performance hybrid halides. Rationally optimizing the photoluminescence performance via accurate structural modulation is one of most important and challenging issues for hybrid halides. Herein, a viable crystal dimensional reduction strategy is proposed to reasonably enhance the photoluminescence quantum yield (PLQY) of hybrid antimony halide. Specifically, a synthetic technique is developed and new 1D [DMPZ]SbCl 5 • H 2 O (DP-SbCl 5 ) is sliced to 0D [DMPZ] 2 SbCl 6 • Cl • (H 2 O) 2 (DP-SbCl 6 ) with crystal dimensional reduction from infinite [SbCl 5 ] 2− chain to discrete [SbCl 6 ] 3− octahedron. Comparing with nonluminescent 1D DP-SbCl 5 , 0D DP-SbCl 6 displays highly efficient broadband yellow light emission with enhanced PLQY up to 75.94%. ...
Intelligent stimuli-responsive fluorescence materials are extremely pivotal for fabricating luminescent turn-on switching in solid-state photonic integration technology, but it remains a challenging objective for typical 3-dimensional (3D) perovskite nanocrystals. Herein, by fine-tuning the accumulation modes of metal halide components to dynamically control the carrier characteristics, a novel triple-mode photoluminescence (PL) switching was realized in 0D metal halide through stepwise single-crystal to single-crystal (SC-SC) transformation. Specifically, a family of 0D hybrid antimony halides was designed to exhibit three distinct types of PL performance including nonluminescent [Ph 3 EtP] 2 Sb 2 Cl 8 ( 1 ), yellow-emissive [Ph 3 EtP] 2 SbCl 5 ·EtOH ( 2 ), and red-emissive [Ph 3 EtP] 2 SbCl 5 ( 3 ). Upon stimulus of ethanol, 1 was successfully converted to 2 through SC-SC transformation with enhanced PL quantum yield from ~0% to 91.50% acting as “turn-on” luminescent switching. Meanwhile, reversible SC-SC and luminescence transformation between 2 and 3 can be also achieved in the ethanol impregnation–heating process as luminescence vapochromism switching. As a consequence, a new triple-model turn-on and color-adjustable luminescent switching of off–on I –on II was realized in 0D hybrid halides. Simultaneously, wide advanced applications were also achieved in anti-counterfeiting, information security, and optical logic gates. This novel photon engineering strategy is expected to deepen the understanding of dynamic PL switching mechanism and guide development of new smart luminescence materials in cutting-edge optical switchable device.
Functionalized gold nanoparticles (AuNPs) have been successfully used in many fields as a result of having low cytotoxicity, good biocompatibility, excellent optical properties, and their ability to target cancer cells. Here, we synthesized AuNP carriers that were modified by hyaluronic acid (HA), polyethylene glycol (PEG), and adipic dihydrazide (ADH). The antitumor drug doxorubicin (Dox) was loaded into AuNP carriers and attached chemically. The Au nanocomposite AuNPs@MPA-PEG-HA-ADH-Dox was able to disperse uniformly in aqueous solution, with a diameter of 15 nm. The results of a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that AuNP carriers displayed very little toxicity toward cells in high doses, although the antitumor properties of Au nanocomposites were significantly enhanced. Cellular uptake experiments demonstrated that AuNPs modified with hyaluronic acid were more readily ingested by HepG2 and HCT-116 cells, as they have a large number of CD44 receptors. A series of experiments measuring apoptosis such as Rh123 and annexin V-FITC staining, and analysis of mitochondrial membrane potential (MMP) analysis, indicated that apoptosis played a role in the inhibition of cell proliferation by AuNPs@MPA-PEG-HA-ADH-Dox. Excessive production of reactive oxygen species (ROS) was the principal mechanism by which the Au nanocomposites inhibited cell proliferation, leading to apoptosis. Thus, the Au nanocomposites, which allowed cell imaging in real-time and induced apoptosis in specific cell types, represent theragnostic agents with potential for future clinical applications in bowel cancer.
InP quantum dots (QDs) are a promising and environment‐friendly alternative to Cd‐based QDs for in vitro diagnostics and bioimaging applications. However, their poor fluorescence and stability severely limit their biological applications. Herein, we synthesize bright (∼100%) and stable InP‐based core/shell QDs by using cost‐effective and low‐toxic phosphorus source, and then aqueous InP QDs are prepared with quantum yield over 80% by shell engineering. The immunoassay of alpha‐fetoprotein can be detected in the widest analytical range of 1–1000 ng ml−1 and the limit of detection of 0.58 ng ml−1 by using those InP QDs‐based fluorescent probes, making it the best‐performing heavy metal‐free detection reported so far, comparable to state‐of‐the‐art Cd‐QDs‐based probes. Furthermore, the high‐quality aqueous InP QDs exhibit excellent performance in specific labeling of liver cancer cells and in vivo tumor‐targeted imaging of live mice. Overall, the present work demonstrates the great potential of novel high‐quality Cd‐free InP QDs in cancer diagnosis and image‐guided surgery.
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