Recent Progress in Lanthanide-Doped Inorganic Perovskite Nanocrystals and Nanoheterostructures: A Future Vision of Bioimaging.

All-inorganic lead halide perovskite nanocrystals have great potential in optoelectronics and photovoltaics. However, their biological applications have not been explored much owing to their poor stability and shallow penetration depth of ultraviolet (UV) excitation light into tissues. Interestingly, the combination of all-inorganic halide perovskite nanocrystals (IHP NCs) with nanoparticles consisting of lanthanide-doped matrix (Ln NPs, such as NaYF4:Yb,Er NPs) is stable, near-infrared (NIR) excitable and emission tuneable (up-shifting emission), all of them desirable properties for biological applications. In addition, luminescence in inorganic perovskite nanomaterials has recently been sensitized via lanthanide doping. In this review, we discuss the progress of various Ln-doped all-inorganic halide perovskites (LnIHP). The unique properties of nanoheterostructures based on the interaction between IHP NCs and Ln NPs as well as those of LnIHP NCs are also detailed. Moreover, a systematic discussion of basic principles and mechanisms as well as of the recent advancements in bio-imaging based on these materials are presented. Finally, the challenges and future perspectives of bio-imaging based on NIR-triggered sensitized luminescence of IHP NCs are discussed.

Encapsulation of Sulfur into N-Doped Porous Carbon Cages by a Facile, Template-Free Method for Stable Lithium-Sulfur Cathode.

Lithium-sulfur (Li-S) batteries with a high energy density and long lifespan are considered as promising candidates for next-generation electrochemical energy-storage devices. However, the sluggish redox kinetics of electrochemistry and high solubility of polysulfide during cycling render insufficient sulfur utilization and poor cycling stability. Herein, a facile, template-free procedure based on controlled pyrolysis of polydopamine vesicles is described to prepare N-doped porous carbon cages (NHSC) as a new sulfur host, which significantly improves both the sulfur utilization and cycling stability. As NHSC shows a high pore volume, continuous electron and ion transport paths, and good catalytic activity, encapsulation of S nanoparticles into NHSC endows the resulting S@NHSC electrode with a good energy storage capacity and exceptionally high electrochemical stability. Consequently, a Li-S cell with the S@NHSC as the cathode achieves a high initial capacity of 1280.7 mAh g-1 , and cycling stability over 500 cycles with the capacity decay as low as 0.0373% per cycle.

Tailoring C60 for Efficient Inorganic CsPbI2 Br Perovskite Solar Cells and Modules.

Although inorganic perovskite solar cells (PSCs) are promising in thermal stability, their large open-circuit voltage (VOC ) deficit and difficulty in large-area preparation still limit their development toward commercialization. The present work tailors C60 via a codoping strategy to construct an efficient electron-transporting layer (ETL), leading to a significant improvement in VOC of the inverted inorganic CsPbI2 Br PSC. Specifically, tris(pentafluorophenyl)borane (TPFPB) is introduced as a dopant to lower the lowest unoccupied molecular orbital (LUMO) level of the C60 layer by forming a Lewis acidic adduct. The enlarged free energy difference provides a favorable enhancement in electron injection and thereby reduces charge recombination. Subsequently, a nonhygroscopic lithium salt (LiClO4 ) is added to increase electron mobility and conductivity of the film, leading to a reduction in the device hysteresis and facilitating the fabrication of a large-area device. Finally, the as-optimized inorganic CsPbI2 Br PSCs gain a champion power conversion efficiency (PCE) of 15.19%, with a stabilized power output (SPO) of 14.21% (0.09 cm2 ). More importantly, this work also demonstrates a record PCE of 14.44% for large-area inorganic CsPbI2 Br PSCs (1.0 cm2 ) and reports the first inorganic perovskite solar module with the excellent efficiency exceeding 12% (10.92 cm2 ) by a self-developed quasi-curved heating method.

A polymer cage as an efficient polysulfide reservoir for lithium-sulfur batteries.

Herein, we present a self-assembly strategy to prepare a cage-polymer coated sulfur sample. The sample embeds graphene as a new sulfur cathode. The cathode exhibits excellent electrochemical stability, maintaining a capacity of 546 mA h g-1 after 495 cycles at 1C, corresponding to an attenuation rate of 0.071% per cycle.

Bilinear Staphylococcus aureus detection based on suspension immunoassay.

A novelty bilinear suspension immunoassay biosensor is developed for Staphylococcus aureus specific detection. In the present study, a dual-color-based sandwich immunosensor was constructed for sensitive and selective detection of this bacterium. In this bioassay system, the monoclonal antibodies of Staphylococcus aureus were immobilized on carboxyl-modified fluorescent microspheres (PSA-R6G) which acted as a capture probe. A secondary fluorescein isothiocyanate (FITC)-labelled antibody of Staphylococcus aureus acted as a sensitive reporter antibody. After dual-labelling with R6G and FITC, the enriched Staphylococcus aureus bacteria were observed by using the multiparameter flow cytometry analysis. In this method, two regression equations were obtained with IFITC = 1.56lgC + 4.50 and IR6G = 1.54lgC + 2.78, respectively. It can be noted that the two slopes were very similar, which indicated the false positives decrease significantly. For general applications, the quantificational measurements of Staphylococcus aureus in milk and water samples were also carried out. The suspension immunoassay exhibited an excellent specificity to Staphylococcus aureus in contrast to conventional culture-based method.