Intense green light emission in Sr2 ZnGe2 O7 :Mn2+ phosphors by the design of high symmetry melilite structure.

A green phosphor Sr2 ZnGe2 O7 :Mn2+ with a melilite structure was prepared using a high-temperature solid-state reaction. When the 535 nm emission was monitored, the excitation spectrum of the Sr2 ZnGe2 O7 :Mn2+ was found to contain two excitation bands in the ultraviolet (UV) region. When excited by UV light, the sample shows bright green emission at 535 nm, which corresponds to the distinctive transition of Mn2+ (4 T1 →6 A1 ). Moreover, the quantum efficiency of Sr2 ZnGe2 O7 :Mn2+ could reach 67.6%. Finally, a high-performance white-light-emitting diode (WLED) with a low correlated colour temperature of 4632 K and a high colour rendering index (CRI) of 92.3 were packaged by coating commercial blue and red phosphors with an optimized Sr2 ZnGe2 O7 :Mn2+ sample on a 310 nm UV chip. This indicated that Sr2 ZnGe2 O7 :Mn2+ has the potential application as a green component in the WLED lighting field.

Dimensional Reduction of Metal-Organic Frameworks for Enhanced Cryopreservation of Red Blood Cells.

To increase the red blood cell (RBC) cryopreservation efficiency by metal-organic frameworks (MOFs), a dimensional reduction approach has been proposed. Namely, 3D MOF nanoparticles are progressively reduced to 2D ultra-thin metal-organic layers (MOLs). We found that 2D MOLs are beneficial for enhanced interactions of the interfacial hydrogen-bonded water network and increased utilization of inner ordered structures, due to the higher surface-to-volume ratio. Specifically, a series of hafnium (Hf)-based 2D MOLs with different thicknesses (monolayer to stacked multilayers) and densities of hydrogen bonding sites have been synthesized. Both ice recrystallization inhibition activity (IRI) and RBCs cryopreservation assay confirm the pronounced better IRI activity and excellent cell recovery efficiency (up to ≈63 % at a very low concentration of 0.7 mg mL-1 ) of thin-layered Hf-MOLs compared to their 3D counterparts, thereby verifying the dimensional reduction strategy to improved cryoprotectant behaviors.

Encoding Coacervate Droplets with Paramagnetism for Dynamical Reconfigurability and Spatial Addressability.

It is an ongoing endeavor in chemistry and materials science to regulate coacervate droplets on a physiologically relevant spatiotemporal scale to ultimately match or even surpass living cells' precision, complexity, and functionality. Herein, we develop a magnetic strategy orthogonal to the thermal, pH, light, or chemical counterparts that are commonly employed by biotic or artificial systems; its successful implementation thus adds a missing piece to the current arsenal of manipulative methodologies. Specifically, we paramagnetize the otherwise diamagnetic coacervate droplets by cooperatively combining paramagnetic ingredients (including organic radicals, metal ions, and Fe3O4 nanoparticles) and coacervate ingredients to obtain "MagCoa" droplets. A simple model is derived theoretically to account for migration and division of MagCoa droplets in an uneven magnetic field. Experimentally, we produce an array of compartmentalized and monodispersed droplets using microfluidics and magnetically steer them with uniformity and synchronicity. We design and fabricate spatial magnetic modulators to engineer the landscape of a magnetic field that, in turn, directs the MagCoa droplets into predesigned patterns in a reconfigurable fashion. These programmable liquid patterns can be potentially extended to dynamic assembly and information encryption. We envision that the toolbox established here is of generality and multitudes to serve as a practical guide to control droplets magnetically.

Long-term whole blood DNA preservation by cost-efficient cryosilicification.

Deoxyribonucleic acid (DNA) is the blueprint of life, and cost-effective methods for its long-term storage could have many potential benefits to society. Here we present the method of in situ cryosilicification of whole blood cells, which allows long-term preservation of DNA. Importantly, our straightforward approach is inexpensive, reliable, and yields cryosilicified samples that fulfill the essential criteria for safe, long-term DNA preservation, namely robustness against external stressors, such as radical oxygen species or ultraviolet radiation, and long-term stability in humid conditions at elevated temperatures. Our approach could enable the room temperature storage of genomic information in book-size format for more than one thousand years (thermally equivalent), costing only 0.5 $/person. Additionally, our demonstration of 3D-printed DNA banking artefacts, could potentially allow 'artificial fossilization'.

A Novel Red-Emitting Na2NbOF5:Mn4+ Phosphor with Ultrahigh Color Purity for Warm White Lighting and Wide-Gamut Backlight Displays.

In this work, a novel red-emitting oxyfluoride phosphor Na2NbOF5:Mn4+ with an ultra-intense zero-phonon line (ZPL) was successfully synthesized by hydrothermal method. The phase composition and luminescent properties of Na2NbOF5:Mn4+ were studied in detail. The photoluminescence excitation spectrum contains two intense excitation bands centered at 369 and 470 nm, which match well with commercial UV and blue light-emitting diode (LED) chips. When excited by 470 nm blue light, Na2NbOF5:Mn4+ exhibits red light emission dominated by ZPL. Notably, the color purity of the Na2NbOF5:Mn4+ red phosphor can reach 99.9%. Meanwhile, the Na2NbOF5:Mn4+ phosphor has a shorter fluorescence decay time than commercial K2SiF6:Mn4+, which is conducive to fast switching of images in display applications. Profiting from the intense ZPL, white light-emitting diode (WLED) with high color rendering index of Ra = 86.2 and low correlated color temperature of Tc = 3133 K is realized using yellow YAG:Ce3+ and red Na2NbOF5:Mn4+ phosphor. The WLED fabricated using CsPbBr3 quantum dots (QDs) and red Na2NbOF5:Mn4+ phosphor shows a wide color gamut of 127.56% NTSC (National Television Standard Committee). The results show that red-emitting Na2NbOF5:Mn4+ phosphor has potential application prospects in WLED lighting and display backlight.