Achieving Narrowed Bandgaps and Blue-Light Excitability in Zero-Dimensional Hybrid Metal Halide Phosphors via Introducing Cation-Cation Bonding

Zero-dimensional(0D)hybrid metal halides,which consist of organic cations and isolated inorganic metal halide anions,have emerged as phosphors with efficient broadband emissions.However,these materials generally have too wide bandgaps and thus cannot be excited by blue light,which hinders their applications for efficient white light-emitting diodes(WLEDs).The key to achieving a blue-light-excitable 0D hybrid metal halide phosphor is to reduce the fundamental bandgap by rational chemical design.In this work,we report two designed hybrid copper(I)iodides,(Ph_(3)MeP)_(2)Cu_(4)I_(6)and(Cy_(3)MeP)_(2)Cu_(4)I_(6),as blue-light-excitable yellow phosphors with ultrabroadband emission.In these compounds,the[Cu_(4)I_(6)]^(2-)anion forms an I6 octahedron centered on a cationic Cu_(4)tetrahedron.The strong cation-cation bonding within the unique cationic Cu_(4)tetrahedra enables significantly lowered conduction band minimums and thus narrowed bandgaps,as compared to other reported hybrid copper(I)iodides.The ultrabroadband emission is attributed to the coexistence of free and self-trapped excitons.The WLED using the[Cu_(4)I_(6)]^(2-)anion-based single phosphor shows warm white light emission,with a high luminous efficiency of 65 Im W^(-1)and a high color rendering index of 88.This work provides strategies to design narrow-bandgap 0D hybrid metal halides and presents two first examples of blue-light-excitable 0D hybrid metal halide phosphors for efficient WLEDs.

Multi-functional bismuth-doped bioglasses: combining bioactivity and photothermal response for bone tumor treatment and tissue repair

Treatment of large bone defects derived from bone tumor surgery is typically performed in multiple separate operations,such as hyperthermia to extinguish residual malignant cells or implanting bioactive materials to initiate apatite remineralization for tissue repair;it is very challenging to combine these functions into a material.Herein,we report the first photothermal(PT)effect in bismuth(Bi)-doped glasses.On the basis of this discovery,we have developed a new type of Bi-doped bioactive glass that integrates both functions,thus reducing the number of treatment cycles.We demonstrate that Bi-doped bioglasses(BGs)provide high PT efficiency,potentially facilitating photoinduced hyperthermia and bioactivity to allow bone tissue remineralization.The PT effect of Bi-doped BGs can be effectively controlled by managing radiative and non-radiative processes of the active Bi species by quenching photoluminescence(PL)or depolymerizing glass networks.In vitro studies demonstrate that such glasses are biocompatible to tumor and normal cells and that they can promote osteogenic cell proliferation,differentiation,and mineralization.Upon illumination with near-infrared(NIR)light,the bioglass(BG)can efficiently kill bone tumor cells,as demonstrated via in vitro and in vivo experiments.This indicates excellent potential for the integration of multiple functions within the new materials,which will aid in the development and application of novel biomaterials.

Correction:Multi-functional bismuth-doped bioglasses:combining bioactivity and photothermal response for bone tumor treatment and tissue repair

In this originally published article,we have noticed several mistakes.They should be corrected as follows:1.On page 1,the second affiliation(No.5)of the author“Chuanbin Mao”should be deleted as he does not belong to that affiliation.Namely,he should be only listed with(Department of Chemistry and Biochemistry Stephenson Life Sciences Research Center,University of Oklahoma,Norman,OK 73072,USA).

Carbon dots embedded in lead-free luminescent metal halide crystals toward single-component white emitters

The development of single-component white emitters for white light-emitting diodes(WLEDs)remains challenging.Herein,a rare earth-free white light-emitting composite is developed by assembling blue-emitting carbon dots(CDs)and yellow-emitting Cs_(2)InCl_(5)·H_(2)O:Sb^(3+)metal halide crystals via a facile liquid-liquid diffusion-assisted crystallization approach.The encapsulation mechanism is then analyzed.Depending on the ratios of blue/yellow emitters,these luminescent composites exhibit white light emission with tunable cold and warm hues.The composites also possess prominent ultraviolet resistance,thermal tolerance,and good stability at about 200°C.By employing such“CDs in metal halide”composites as a converter,a WLED is successfully fabricated with a high color rendering index of 93.6,benefiting from the assembled blue and yellow broadband emission.With this strategy,the developed composites show great promise in next-generation WLED lighting.

Bismuth-doped germanate glass fiber fabricated by the rod-in-tube technique

Bismuth （Bi）-doped laser glasses and fiber devices have aroused wide attentions due to their unique potential to work in the new spectral range of 1 to 1.8 μm traditional laser ions, such as rare earth, cannot reach. Current Bi-dopcd silica glass fibers have to be made by modified chemical vapor deposition at a temperature higher than 2000℃. This unavoidably leads to the tremendous loss of Bi by evaporation, since the temperature is several hundred degrees Celsius higher than the Bi boiling temperature, and, therefore, trace Bi （-50 ppm） resides within the final product of silica fiber. So, the gain of such fiber is usually extremely low. One of the solutions is to make the fibers at a temperature much lower than the boiling temperature of Bi. The challenge for this is to find a lower melting point glass, which can stabilize Bi in the near infrared emission center and, meanwhile, does not lose glass transparency during fiber fabrication. None of previously reported Bi-doped multicomponent glasses can meet the prerequisite. Here, we, after hundreds of trials on optimization over glass components, activator content, melting temperature, etc., find a novel Bi-doped gallogermanate glass, which shows good tolerance to thermal impact and can accommodate a higher content of Bi. Consequently, we successfully manu- facture the germanate fiber by a rod-in-tube technique at 850℃. The fiber exhibits similar luminescence to the bulk glass, and it shows saturated absorption at 808 nm rather than 980 nm as the incident power becomes higher than 4 W. Amplified spontaneous emissions are observed upon the pumps of either 980 or 1064 nm from ger- manate fiber.

Lattice Doping of Lanthanide Ions in Cs_(2)AgInCl_(6)Nanocrystals Enabling Tunable Photoluminescence

Lead-free halide double perovskite Cs_(2)AgInCl_(6 )has become the research hotspot in the optoelectronic fields.It is a challenge to utilize the lattice doping by different lanthanide ions with rich and unique photoluminescence(PL)emissions for emerging photonic applications.Here,we successfully incorporated Dy^(3+),Sm^(3+),and Tb3+ions into Cs_(2)AgInCl_(6) nanocrystals(NCs)by the hot-injection method,bringing diverse PL emissions of yellowish,orange,and green light in Cs_(2)AgInCl_(6):Ln^(3+)(Ln^(3+)=Dy^(3+),Sm^(3+),Tb^(3+)).Moreover,benefiting from the energy transfer process,Sm^(3+)and Tb^(3+)ion-codoped Cs_(2)AgInCl_(6) NCs achieved tunable emission from green to yellow orange and a fluorescent pattern from the as-prepared NC-hexane inks by spray coating was made to show its potential application in fluorescent signs and anticounterfeiting technology.This work indicates that lanthanide ions could endow Cs_(2)AgInCl_(6) NCs the unique and tunable PL properties and stimulate the development of lead-free halide perovskite materials for new optoelectronic applications.

Multi-responsive deep-ultraviolet emission in praseodymium-doped phosphors for microbial sterilization

Perusing multimode luminescent materials capable of being activated by diverse excitation sources and realizing multi-responsive emission in a single system remains a challenge.Herein,we utilize a heterovalent substituting strategy to realize multimode deep-ultraviolet(UV)emission in the defect-rich host Li_(2)CaGeO_(4)(LCGO).Specifically,the Pr^(3+)substitution in LCGO is beneficial to activating defect site reconstruction including the generation of cation defects and the decrease of oxygen vacancies.Regulation of different traps in LCGO:Pr^(3+)presents persistent luminescence and photo-stimulated luminescence in a synergetic fashion.Moreover,the up-conversion luminescence appears with the aid of the 4f discrete energy levels of Pr^(3+)ions,wherein incident visible light is partially converted into germicidal deep-UV radiation.The multi-responsive character enables LCGO:Pr^(3+)to response to convenient light sources including X-ray tube,standard UV lamps,blue and near-infrared lasers.Thus,a dual-mode optical conversion strategy for inactivating bacteria is fabricated,and this multi-responsive deep-UV emitter offers new insights into developing UV light sources for sterilization applications.Heterovalent substituting in trap-mediated host lattice also provides a methodological basis for the construction of multi-mode luminescent materials.