Search

Fiber‐based inorganic thermoelectric (TE) devices, owing to the small size, light‐weight, flexibility, and high TE performance, are promising for applications in flexible thermoelectrics. Unfortunately, current inorganic TE fibers are strictly constrained by limited mechanical freedom because of the undesirable tensile strain, typically limited to a value of 1.5%, posing a strong obstacle for further application in large‐scale wearable systems. Here, a superflexible Ag2Te0.6S0.4 inorganic TE fiber is demonstrated that provides a record tensile strain of 21.2%, such that it enables various complex deformations. Importantly, the TE performance of the fiber shows high stability after ≈1000 cycles of bending and releasing processes with a small bending radius of 5 mm. This allows for the integration of the inorganic TE fiber into 3D wearable fabric, yielding a normalized power density of 0.4 µW m−1 K−2 under the temperature difference of 20 K, which is approaching the high‐performance Bi2Te3‐based inorganic TE fabric and is nearly two orders of magnitude higher than the organic TE fabrics. These results highlight that the inorganic TE fiber with both superior shape‐conformable ability and high TE performance may find potential applications in wearable electronics. [ABSTRACT FROM AUTHOR]

Ultrafast fiber lasers, due to their short pulse duration, excellent beam quality, and high brightness, are extensively used in precision processing, biomedicine, nonlinear optics, and spectroscopy. However, great challenges still exist in improving the optical conversion efficiency in glass‐based gain media because of the high non‐radiative transition probability. Here, we demonstrate an oxyfluoride glass–ceramic (GC) fiber containing NaYF4:Yb3+ nanocrystal that enables enhanced 1064‐nm continuous‐wave laser output with an optical signal‐to‐noise ratio of 60 dB. Compared with the as‐prepared glass fiber, the optical conversion efficiency of GC fiber is improved from 24.2% to 30.0%. The improvement of laser action is mainly caused by the preferential incorporation of Yb3+ into the NaYF4 nanocrystal with low phonon energy. Using this well‐developed GC fiber, we successfully built a passively mode‐locked pulsed fiber laser that deliveries laser pulses with a pulse duration of 8.1 ps and a repetition frequency of 56.92 MHz. These results highlight that the GC strategy may provide a roadmap for the development of ultrafast fiber laser and the application of GC fibers in various optoelectronic fields. [ABSTRACT FROM AUTHOR]

The glass-forming ability, crystallization behavior and physical properties of GeS 2 -Sb 2 S 3 -CsX (X = Cl, Br, I) glasses and glass-ceramics (GCs) are systematically studied by various characterization techniques. With the introduction of cesium halides, transparent chalcogenide GCs containing the single nanocrystals of CsX can be obtained in a controlled fashion. The crystallization behavior was investigated in the line of (100- x) (0.5GeS 2 -0.5Sb 2 S 3)- x CsX glasses. IR-transmitting chalcogenide GCs embedded with CsCl and CsBr nanocrystals of a large crystallinity have been fabricated successfully after thermal treatments, whereas surface crystallization of CsI is dominated in GeS 2 -Sb 2 S 3 –CsI glassy samples. Such distinct crystallization behaviors of CsX crystal phases are compared and discussed with microstructural results. We propose that the ionic diffusion ability of halogen in the GeS 2 -Sb 2 S 3 -CsX glassy network determines the nucleation and crystal growth of CsX. This finding is of guidance meaning for future design of chalcogenide GCs with novel optical functions and microstructures. [ABSTRACT FROM AUTHOR]

Fiber lasers, owing to the high beam quality and super robustness, are widely used in fields from optical communications, fiber sensing, biomedicine to material processing. The use of glass fibers as the gain medium has, however, posed a strong obstacle for improving efficiency and, especially, achieving efficient lasing action in the mid‐infrared (MIR) region, because of the relatively large nonradiative energy loss. Here, the fabrication of a Tm3+‐doped tellurate glass‐ceramic (GC) fiber is demonstrated, which enables enhanced lasing action at ≈2 µm. Compared with the as‐prepared fiber, the optical conversion efficiency of GC fiber is increased from 8.8% to 14.1%. The microstructure and spectral characterization analyses suggest that the improvement of the laser performance in GC fiber is induced by the significant change of the local environment surrounding Tm3+ ions due to the formation of nanocrystals within the glass fibers. Moreover, the developed GC fiber also enables Q‐switched pulsed laser output at ≈2 µm with a pulse energy of 3.2 J and pulse width of 4.1 ns. The results demonstrated here may have strong implications in the development of MIR fiber lasers and the applications of GC fibers in MIR photonics. [ABSTRACT FROM AUTHOR]

Transparent glass ceramics (GCs) consisting of an homogeneous glass phase and a well‐dispersed crystal phase are considered as ideal optical gain materials potentially applied in optoelectronic devices due to the combination of facile processability of glass and the intense crystal field of nanocrystals. Here, a heat‐induced nanocrystal‐in‐glass method is employed to integrate the active ions Tm3+ into Bi2Te4O11 nanocrystals with an intense crystal field to realize an enhanced microlaser output. This strategy endows the efficient tellurate GC microcavity laser operating at ≈2 µm. Compared with the laser properties of as‐prepared glass microcavities, the pump threshold (260 µW) is as low as less than a quarter and the slope efficiency (0.0296%) is 5.5 times higher. Furthermore, by carefully engineering the heat treatment temperature and duration, the crystal size and distribution can be precisely controlled. Thus, the Rayleigh scattering loss that is detrimental to quality (Q) factor is effectively suppressed and the GC microcavities with high Q factors up to 105 are successfully obtained. This work provides useful insight on the development of optical functional materials and expands the practical applications of GC microcavities in various optoelectronic fields. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) glass-converted light-emitting diodes (gc-LEDs) are newly emergent broadband light sources for miniaturizing optical systems like spectrometers. While lots of effort has been spent on materials doped with rare-earth and transition-metal ions, the achievement of these materials with broadband NIR emission and desired wavelength region remains a long-standing challenge, especially operating in the spectral region between 700 and 1100 nm. Herein, a broadband NIR LEDs based on Te cluster-doped silicate glass is developed. Through adjustment of melting atmosphere and network topology of the glass matrix, active NIR Te cluster centers can be generated and stabilized in silicate glass and show a broad emission at 980 nm with a full width at half maximum (FWHM) of 300 nm under blue light excitation. The photoluminescence of the glass matches well with the absorption of several primary chemical bonds in food and biological tissue. In demonstration experiments, the NIR absorption of different biological tissue by NIR light from our glass is measured, suggesting that the super-broad NIR luminescence of Te-doped silicate glass has potential applications as light sources for nondestructive analysis. [ABSTRACT FROM AUTHOR]

Abstract: It is well recognized that a widely wavelength‐tunable mid‐infrared (MIR) fiber laser plays an important role in the development of compact and efficient coherent sources in the MIR range. Herein, the optimizing Er/Ho ratio for enhancement of broadband tunable MIR emission covering 2.6‐2.95 μm in the Er3+/Ho3+‐codoped transparent borosilicate glass‐ceramic (GC) fibers containing NaYF4 nanocrystals under 980 nm excitation was investigated. Specifically, the obtained GC fibers with controllable crystallization and well fsd‐maintained structures were prepared by the novel melt‐in‐tube approach. Owing to the effective energy transfer between Er3+ and Ho3+ after crystallization, the 2.7 μm MIR emission was obviously enhanced and the emission region showed a notable extension from 2.6‐2.82 μm to 2.6‐2.95 μm after the addition of Ho3+. Importantly, we conducted a theoretical simulation and calculation related to the MIR laser performance, signifying that the GC fiber may be a promising candidate for MIR fiber laser. Furthermore, the melt‐in‐tube approach will provide a versatile strategy for the preparation of diverse optical functional GC fibers. [ABSTRACT FROM AUTHOR]

Transparent oxyfluoride glass ceramics (GCs) comprised of a uniform oxide glass phase and a well-distributed fluoride crystal phase are regarded as suitable optical gain materials because of the combination of facile fabricability of glass and low phonon energy of nanocrystals. Here, oxyfluoride GCs containing NaYF 4 : Er3+/Ho3+/Dy3+ nanocrystals were controllably prepared. Due to the preferential incorporation of rare-earth ions into NaYF 4 nanocrystals with low phonon energy and the efficient energy transfer between active ions, enhanced and broadband mid-infrared (MIR) emission at 2.5–3.3 µm was obtained from the GCs, which was nearly unobserved in precursor glass (PG) because of the high phonon energy of glass matrix. Compared with Er3+ singly-doped sample, the full width at half maximum (FWHM) is more than 3 times broader in Er3+/Ho3+/Dy3+ triply-doped sample. Furthermore, by the match of the refractive index of glass with NaYF 4 nanocrystal, transparent GCs with average crystal size of 80 nm and high transmittance over 80% were achieved simultaneously. The desirable optical properties endow the GCs with potential applications in MIR broadband tunable lasers. • Enhanced and broadband MIR emission at 2.5–3.3 µm in glass ceramics (GCs) are achieved. • The FWHM of the MIR emission is broadened more than 3 times after co-doping. • GCs with average crystal size of 80 nm and high transmittance over 80% are obtained. • The transmittance of GCs is theoretically analyzed based on Mie scattering theory. [ABSTRACT FROM AUTHOR]

Chalcogenide solid states electrolytes (SSEs) are considered as one of the most promising alternative to replace liquid electrolytes for their high ionic conductivity and appropriate mechanical properties. However, the commercial applications of chalcogenide SSEs in all-solid lithium-ion batteries (ASSIBS) are still limited by the inferior interfacial stability, which leads to lithium dendrite growth and continual interphase formation. Here, the interfacial stability of Li 2 S–P 2 S 5 –B 2 S 3 SSEs have been enhanced effectively via LiI incorporation. In detail, a series of (100- x) (75Li 2 S–15P 2 S 5 –10B 2 S 3)- x LiI (x = 0, 5, 15, 30, 40) SSEs are prepared via ball-milling and then melt-quenching, which exhibit a high ionic conductivity of 1.53 mS cm−1 and a steady long cycling life up to 1637 h without obvious resistance growth at 0.1 mA cm−2. This excellent cycle life is originated from the electronic insulation interphase containing LiI without unaltered the "multi-layer mosaic like" structure of Li 2 S–P 2 S 5 –B 2 S 3 ternary glass system. In addition, this work also confirmed that LiI can act as a catalyst to enhance the charge transfer kinetics within S composite electrode thereby reducing the interface impedance. The stable interface performance obtained by this work could facilitate the development of ASSIBS with prolonged cycle life. [ABSTRACT FROM AUTHOR]

Nanocrystallized glass ceramics (NGCs) are important optical materials, but few studies have focused on their laser actions. Here, by precipitation of NaYF4 nanocrystals enriched with Er3+ ions in an oxide glass matrix, great enhancement of the luminescence properties for the NGC microspheres is realized. By carefully matching the refractive index of the glass matrix with that of the NaYF4 nanocrystals and controlling the size and distribution of the precipitated nanocrystals, the absorption and Rayleigh scattering losses that are harmful to quality (Q) factors are efficiently suppressed. As a result, the NGC microsphere cavities present ultrahigh Q factors up to 106 (@ 1610 nm), which is slightly lower than that of the microsphere cavities made by precursor glass. Moreover, single mode whispering gallery modes (WGMs) lasing from the NGC microsphere cavities for the first time is successfully realized. Compared with the microsphere cavity based on glass, the NGC microsphere cavity exhibits large enhancement of the pumping efficiency by more than 7 times and a decrease in the threshold by more than 2.5 times. The results demonstrated here suggest a novel method for improving the laser output performances of microcavities, which may have potential applications in areas of photonics and optical communication. [ABSTRACT FROM AUTHOR]

Broadband near-infrared (NIR) spectroscopy based on glass-converted light-emitting diodes (gc-LEDs) has been of great interest to multifunctional applications ranging from night vision to chemical industry, stimulating the demand for exploring broadband NIR gc-LEDs with sufficient efficiency stability and aging resistance. Herein, an all-inorganic broadband NIR LEDs based on Te cluster-doped germanate glass is developed. Via adjustment of melting atmosphere and network topology of the glass matrix, active NIR Te cluster centers can be generated and stabilized in germanate glass and show a broad emission at 770 nm with a full width at half maximum (FWHM) of 260 nm under blue light excitation. By combining the Te-doped glass with a commercial blue LED chip, a high-performance NIR gc-LEDs is fabricated with an NIR output power of 14.21 mW@10.1% under a driving current of 400 mA. Particularly, the fabricated NIR-LED device exhibits high efficient stability with a relatively low-efficiency drop of 0.0023 %mA−1, and excellent aging resistance while retaining an electroluminescence intensity up 90 % of their initial value after aging for 480 h under harsh conditions, which is comparable to the commercial phosphors. Finally, its multifunctional application of gc-LEDs is also demonstrated. [ABSTRACT FROM AUTHOR]

Among the chalcogenide solid-state electrolytes (SSEs), Na 3 SbS 4 is of particular importance because of its high ionic conductivity and compatibility with moist air, which reduces processing costs and favors large-scale industrial deployment. However, the cation doping effects on the electrochemical properties of the Na 3 SbS 4 remain elusive. Here, a series of Na (3-2x) Sb (1-x) Mo x S (4-x) I x (x = 0.05, 0.1 0.15, 0.2) SSEs were fabricated via the ball milling and melt quenching strategy. The valence state of Mo is revealed to be 4+ not 6+. A high ionic conductivity of 0.54 mS cm−1 and an excellent critical current density of 1.5 mA cm−2 was obtained at room temperature. The cycling life of the symmetric cell is up to 112 h. The as-prepared SSEs also exhibit outstanding chemical stability. This work provides insightful understanding of the valence state of cations and impacts on the electrochemical performance of chalcogenide SSEs, which are vital for designing optimal SSEs. [ABSTRACT FROM AUTHOR]

All‐solid‐state sodium ion batteries (ASSIBs) attract growing attention as the next generation of batteries due to their high energy density, excellent safety, and the abundance of sodium resources. As a vital component of ASSIBs, chalcogenide Na‐ion solid‐state electrolytes (SSEs) have been widely studied due to their high ionic conductivity and outstanding ductility. However, due to the susceptibility to organic solvents and moisture, no chalcogenide Na‐ion SSEs membrane has been reported while only thick SSEs pellets have been investigated, which introduces abundant "dead" weight and lowers the energy density of ASSIBs. Herein, utilizing the excellent air stability of Na3SbS4, a thin (∼220 μm) Na3SbS4 membrane is prepared in air via a facile dry‐film method with polytetrafluoroethylene fibrillation, which exhibits a high ionic conductivity of 0.19 mS cm and an excellent critical current density of 0.6 mA/cm2. In summary, the chalcogenide Na‐ion SSEs membranes with high ionic conductivity and the simple preparation process could be readily adopted by pragmatic high‐performance ASSIBs. [ABSTRACT FROM AUTHOR]

Optical modulation is a crucial operation in photonics for network data processing with the aim to overcome information bottleneck in terms of speed, energy consumption, dispersion and cross-talking from conventional electronic interconnection approach. However, due to the weak interactions between photons, a facile physical approach is required to efficiently manipulate photon-photon interactions. Herein, we demonstrate that transparent glass ceramics containing LaF3: Tm3+ (Er3+) nanocrystals can enable fast-slow optical modulation of blue/green up-conversion fluorescence upon two-step excitation of two-wavelengths at telecom windows (0.8-1.8 μm). We show an optical modulation of more than 1500% (800%) of the green (blue) up-conversion fluorescence intensity, and fast response of 280 μs (367 μs) as well as slow response of 5.82 ms (618 μs) in the green (blue) up-conversion fluorescence signal, respectively. The success of manipulating laser at telecom windows for fast-slow optical modulation from rear-earth single-doped glass ceramics may find application in all-optical fiber telecommunication areas. [ABSTRACT FROM AUTHOR]

Rare earth (RE) ions‐doped luminescent nanocrystals (NCs) with numerous unique advantages have attracted tremendous interest for the wide applications from science to engineering, yet suffering from the shortcoming of thermal quenching coming from surface organic ligands. We propose utilizing a facile acid‐base reaction to remove surface organic ligands introduced choosing carboxylic acids as stabilizing agent and weaken thermal quenching. The results showed that the acid‐base reaction displayed an outstanding cleaning effect. After acid‐treatment, most surface organic ligands were removed, and there was no influence on crystal structure and morphology of as‐prepared β‐NaYF4:Er3+ NCs. Meanwhile, with no surface organic ligands capping, β‐NaYF4:Er3+ NCs preferred brighter emission after thermal treatment, including up‐conversion (UC), near‐infrared (NIR), and mid‐infrared (MIR) emission. When calcined the acid‐treated β‐NaYF4:Er3+ NCs in different atmosphere, such as oxygen and reducing atmosphere (15%H2 + 85%N2), an unexpected enhancement of all emission bands in Er3+ was determined under phase transformation temperature, especially in oxygen atmosphere. Furthermore, all the fluorescence lifetimes of Er3+ also exhibited obvious extension. Our results supposed that the β‐NaYF4:Er3+ NCs have promising applications in safety ink, and the acid‐treatment by diluted hydrochloric acid is a general approach to remove deleterious organic ligands on NC surface further to weaken thermal quenching. [ABSTRACT FROM AUTHOR]

Anti-reflective (AR) films have been widely investigated due to their various applications in optoelectronic devices. Among all the investigation, the manufacturing method is the most popular research field which directly determines the performance of anti-reflective films. Herein, Na 2 HPO 4 and AlCl 3 mixed neutral solution were used to etch the surface of K9 glass matrix to obtain the AR structure. The morphology of SEM images indicated that subwavelength structure (SWS) was formed on the glass surface via precisely controlling the solution concentration, treatment time and temperature. Owing to the porous structure, the refractive index mutation of the interface between air and glassss can be effectively weakened. Therefore, the integral transmittance, covering the whole visible light (VIS) to near-infrared (NIR) wavelength (300–2500 nm), of glass matrix was increased remarkably to 95.77%, much higher than 87.72% of blank glass, achieving the effect of ultra-wideband anti-reflection. Particularly, the transmittance at 520 nm and 1990 nm can even reach to 99.14% and 97.86%, respectively. According to the composite analysis and reaction process, Al3+ ions act as both the regulator of the solution pH and part of the new-formed glass skeleton, resulting in the more uniform and regular SWS on the glass surface. Moreover, in virtue of -OH in silanol (Si-OH) on the expanded glass surface attracting more H 2 O molecules or additional silylation modification on glass surface repulsing H 2 O molecules, the surface characteristics of AR glass with SWS films can be easily turned between hydrophilic and hydrophobic in order to meet the requirements of various application environments. These ultra-wideband AR glasses with controllable hydrophilic and hydrophobic properties are expected to be applied in many optoelectronic fields. [ABSTRACT FROM AUTHOR]

Gradient index (GRIN) lens could promote the lightweight and miniaturization of optical imaging system, but the development of IR GRIN lens is still in its infancy. A new series of As–S–Se chalcogenide glasses (ChGs) possessing similar glass transition temperature, excellent thermal stability, and large refractive index variation was developed, and these properties enabled them to become a good glass material catalog for co-molding multilayered GRIN IR lens. By employing precision molding, layer-stacked GRIN ChG was co-molded with a maximum refractive index variation of 0.47 at 4 μm, which was correlated to the variation of Raman intensity and elemental content. A mid-IR optical imaging system was designed and fabricated using the GRIN ChGs, and IR images were obtained. This multilayered GRIN ChG could lead to 18% smaller and 35% lighter SWaP IR optical system. [ABSTRACT FROM AUTHOR]

In current work, transparent fluorosilicate glass-ceramics (GCs) containing NaYF 4 :Er 3+ nanocrystals were successfully prepared by controlled heat treatment process. The thermal properties and crystallization characteristic temperatures were determined by the differential scanning calorimetry (DSC). The X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to confirm the formation of NaYF 4 nanocrystals in glass matrix. Energy dispersive spectrometer (EDS) results and Judd-Ofelt (J-O) parameters analysis demonstrated the incorporation of Er 3+ into NaYF 4 nanocrystals. Intense 2.7 μm luminescence was observed in Er 3+ -doped GCs upon excitation with a 980 nm laser diode (LD). Furthermore, the effect of different alkali metals (Li + , Na + , K + ) on crystallization characteristics and luminescent properties has been studied in detail, which indicates Li + is the most favorable option for mid-infrared luminescence properties compared with Na + and K + . The excellent spectroscopic characteristics suggest that the obtained GCs may be promising materials for mid-infrared fiber lasers. [ABSTRACT FROM AUTHOR]

Abstract: White lasers are promising illuminants for emerging visible light communication, which can overcome bottlenecks of lower energy conversion efficiencies and output powers in traditional white light‐emitting (WLE) diodes. However, optical gain materials for white lasers are suffering from great challenges of material growth and growth‐compatible cavity structure where lasing of all three elementary colors can be supported simultaneously. Here, an exquisite physical strategy is demonstrated to realize simultaneous red, green, and blue (RGB) upconversion (UC) photoluminescence for white light modulation for the first time, namely using dual lasers at 850 and 980 nm to stimulate easy‐fabricated glass ceramics (GCs) fiber laser materials (Pr3+ single‐doped germanium oxyfluoride GCs). It is shown that tailorable white light is much more sensitive to lower dopant concentration for GCs than that for glass. Furthermore, compared to glass, UC fluorescence intensities in GCs have approximately two orders of magnitude enhancement. The feasibility of the judicious dual‐lasers excitation tactic is validated for high efficacious RGB fluorescence emission for white light from Pr3+ single‐doped GCs via electronics transition dynamics and theoretical calculations. The white light emission from Pr3+ single‐doped GCs, adjusted by simultaneous dual‐lasers excitation, may open a novel door to develop white light GCs fiber lasers for application in future wireless communication. [ABSTRACT FROM AUTHOR]

Chalcogenides with high ionic conductivity and appropriate mechanical properties are promising solid‐state electrolytes (SSEs) to substitute current liquid electrolytes in lithium‐ion batteries. Yet, their practical applications in all‐solid‐state batteries are still retarded by both the low critical current density and the inferior interfacial stability toward electrodes. In this work, a series of superior SSEs, that is, Li2S‐P2S5‐B2S3 electrolytes, are developed via a ball‐milling and then melt‐quenching strategy. These SSEs exhibit a high critical current density of 1.65 mA cm−2 and a long cycling life of over 300 h. In addition, the evolution mechanism of the interphase between SSEs and metallic lithium is revealed via operando electrochemical impedance spectroscopy, depth‐profiling XPS, and in situ Raman spectroscopy. The structural and chemical heterogeneities are found to be the main origins of the continual interphase evolution. The resulting "multi‐layer mosaic like" interphase facilitates the suppression of Li dendrite growth, and hence, prolongs the lifetime of lithium‐ion all‐solid‐state batteries. In addition, the preparation technique of SSEs developed in the present work is feasible for scale‐up production. [ABSTRACT FROM AUTHOR]

Efficient optical modulation enables a significant improvement of optical conversion efficiency and regulation of optical response rate, showing great potential for optoelectronics applications. However, the weak interaction between photons poses a strong obstacle for manipulating photon–photon interactivity. Here, upon simultaneous excitation of 850 and 1550 nm, a fast–slow optical modulation of green up‐conversion (UC) luminescence in oxyfluoride glass ceramics containing NaYF4:Er3+ nanocrystals can be achieved. Compared with the sum of luminescence intensity excited by the two single‐wavelengths, green UC luminescence excited by simultaneous two‐wavelength presents an obvious increase by approximate six times. Interestingly, the response rate of green UC luminescence relies on the pump strategy of two‐wavelength excitation, showing as high as two times of the fast–slow response difference. The fast–slow optical modulation of green UC luminescence under two‐wavelength excitation is promising for emerging applications in all‐optical switching. [ABSTRACT FROM AUTHOR]

Chalcogenide solid‐state electrolytes (SSEs) have been receiving growing attentions due to their high ionic conductivity and suitable mechanic properties, especially the Li2S–P2S5 systems incorporated with a second glass network formers (Si, Ge, Sn, and so on) besides P. Although the ionic conductivities are generally enhanced with the second glass network formers, the comprehensive effects of different glass formers on other properties, including electrochemical, cycling, and air stability, remain elusive. To acquire deeper understanding, herein, three common but representative glass network formers (SiS2, GeS2, and SnS2) were introduced into Li2S–P2S5, and their individual effects were investigated systematically. The results of multiscale characterizations before and after lithium stripping/plating cycling confirmed that the introduction of metal cations (Ge, Sn) generally leads to worse electrochemical stability and shorter cycle life of these SSEs toward lithium metal compared with SSEs with nonmetal cation (Si) modification. However, the air stability is related to the binding energy of M–S (M = Si, Ge, Sn), which is consistent with the hard base soft acid theory. This work provides valuable understanding for designing pragmatic Li2S–P2S5–MS2‐based SSEs with high electrochemistry, cycling, and air stability. [ABSTRACT FROM AUTHOR]

The confinement of CsPbX 3 (X = Cl, Br, and I) perovskite nanocrystals (NCs) in a stabilized inorganic glass matrix is a new strategy for improving their long-term stability and promoting their applications in the optoelectronic field. Here, in situ nanocrystallization strategy is developed to precipitate CsPbBr 3− x I x NCs with arbitrary I/Br ratio among an elaborately designed GeS 2 –Sb 2 S 3 -based chalcogenide glass matrix. Spherical CsPbBr 3− x I x NCs are homogeneously distributed in the glass matrix after thermal treatment. The photoluminescence (PL) spectra show that the emission peaks of CsPbBr 3− x I x NCs can be tuned from 570 nm to 722 nm with the replacement of Br by I. The fs transient absorption (TA) spectra reveal that there exists some structural defects in the NCs, leading to short PL decay life. This work would shed light on confining CsPbX 3 NCs into glassy matrices, facilitating their future applications in photoelectronic fields. [ABSTRACT FROM AUTHOR]

Rational design and fabrication of multicolor fluorescent sources represent one of the significant challenges in the development of high‐performance solid‐state lighting, tunable coherent lasing, and full‐color display technologies. However, generation of simultaneous multicolor emission, especially white light generation with a wide color gamut is usually beyond the ability of a single material. Heterogeneous structures made by combinations of red, green, and blue emission building blocks are bulky, inefficient, complicated, and costly. Here reported is a bottom‐up strategy to generate simultaneous multicolor emission with continuous tunability in a single monolithic material based on the "nanocrystals‐in‐glass composite" (NGC) architecture. In this approach, a self‐sustained low‐temperature solution combustion process enables homogeneous solvent dispersion and eventually stable immobilization of multiple nanocrystals in transparent matrix. With transparency of up to 80%, further demonstrated is drawing of fiber from the melt of these combustion‐processed NGC materials. The optical spectra of the as‐drawn glass fiber can be precisely tuned and clustering is effectively suppressed. Moreover, the NGC materials exhibit remarkable anti‐thermal quenching behavior at temperatures of up to 200 °C. The bottom‐up strategy for NGC provides a versatile platform for the fabrication of high‐performance multifunctional fiber‐based devices for advanced applications in lasers, illumination, displaying, and biophotonics. [ABSTRACT FROM AUTHOR]

• A robust tungsten tellurite glass fiber was fabricated by extrusion method. • 70TZLW glass exhibits higher T g and ΔT than those of TeO 2 -ZnO-Na 2 O glasses. • The average bending strength of 70TZLW fiber is about 570 MPa, which exceeds that of fluoride fibers by>30 %. Robust tungsten tellurite (70TZLW) glass fiber consisting of 70TeO 2 -16ZnO-4La 2 O 3 -10WO 3 core and 70TeO 2 -16ZnO-5.5La 2 O 3 -8.5WO 3 cladding (in mol.%) was prepared by extrusion method. Due to the adding of La 2 O 3 and WO 3 , 70TZLW glass exhibits higher glass transition temperature (385–395 °C) and thermal stability (>145 °C) than those of TeO 2 -ZnO-Na 2 O glasses, which is beneficial to the drawing of optical fiber. In addition, the mean optical losses of the bare wires drawn by the core and cladding glass preform are about 1.19 dB/m and 1.16 dB/m, while that is about 1.04 dB/m for the fiber drawn from the accordingly extruded preform at the wavelength of 1310 nm. Moreover, the average mechanical bending strength of the fiber reaches to about 570 MPa with a Weibull slope of 67.4. These results show the improvement in work ability and the greater practical potential of the 70TZLW extruded fiber compared to TeO 2 -ZnO-Na 2 O fibers for infrared application. [ABSTRACT FROM AUTHOR]

Rare earth doped mid-infrared (MIR) fluorescent sources have been widely investigated due to their various potential applications in the fields of communication, chemical detecting, medical surgery and so forth. However, with emission wavelength extended to MIR, multiphonon relaxation process that strongly quenched the MIR emission is one of the greatest challenges for such practical applications. In our design, we have described a controllable gas-aided annealing strategy to modulate the phase, crystal size, morphology and fluorescent performance of a material simultaneously. Uniform and monodispersed Er3+-doped La2O2S and La2O2SO4 nanocrystals with a similar lattice structure, crystallinity, diameter and morphology have been introduced to investigate the impact of multiphonon relaxation on luminescence performance. Detailed spectroscopic evolutions in the region of MIR, near-infrared (NIR), visible upconversion (UC) and their corresponding decay times provide insight investigation into the fluorescent mechanism caused by multiphonon relaxation. A possible energy transfer model has also been established. Our results present direct observation and mechanistic investigation of fluorescent evolution in multiphonon relaxation process, which is conductive to design MIR fluorescent materials in the future. To the best of our knowledge, it is the first investigation on MIR fluorescent performance of La2O2S nanocrystals, which may find various applications in many photoelectronic fields. [ABSTRACT FROM AUTHOR]

Mid-infrared (MIR) laser operating at 2–5 μm has gained increasing interest because of the extensive applications in fields from biomedicine, sensing to nanomaterial science. Chalcogenide glass (ChG) is a kind of matrix that is promising for MIR laser due to its low phonon energy and wide infrared transmittance region. However, significant challenges in the enhancement of MIR optical properties of rare-earth ion-doped ChGs still exist. Here, enhanced MIR emission was realized in Pr3+-doped chalcogenide glass ceramics (ChGCs). By controlling the heat treatment temperature and duration, biphasic-phase nanocrystals of Ga 2 Se 3 and GeSe 2 were successively precipitated in the glass host. Compared to the as-prepared glass, the GCs exhibit an obvious increase in emission intensity by more than 5 times. The improvement of the MIR emission may be induced by the enhanced cross-relaxation between Pr3+ ions and the increased multiple scattering effects. Furthermore, the obtained ChGC enables large stimulated emission cross section 0.42 × 10−20 cm2 at 2.44 μm and 0.62 × 10−20 cm2 at 4.75 μm. The superior optical properties of the ChGC indicate that it is an attractive candidate for MIR laser. • Biphasic-phase nanocrystals of Ga 2 Se 3 and GeSe 2 embedded glass-ceramic was prepared by controlled heat treatment. • Enhanced MIR emission of Pr3+ was observed in the glass ceramics. • Effect of biphasic-phase nanocrystals on the enhancement of MIR emission was investigated. • The glass-ceramic with large stimulated emission cross section endows its potential application in MIR laser. [ABSTRACT FROM AUTHOR]

• Sn effect on glass-forming ability was studied. • Long-wavelength cut-off edge was extended. • Optical properties of Sn-modified ChGs were characterized. • Homogeneous ChG of Φ30 mm was prepared successfully. Chalcogenide glass is emerging as important IR materials for advanced athermal infrared (IR) optical systems because of its low thermal coefficient of refractive index. New chalcogenide glasses based on 75GeS 2 -15Ga 2 S 3 -10CsCl were developed through the substitution of GeS 2 by SnS 2. The introduction of heavier tin (Sn) results in the red shift of transmission window, both of visible and long-wavelength IR cut-off edges, the elevation of refractive index dispersion curves, and the decreasing of glass transition temperature. The formation of [SnS 4-x Cl x ] structural units, instead of [GeS 4-x Cl x ], should be responsible for the variation of these structural properties. In addition, homogeneous Sn modified GeS 2 -Ga 2 S 3 -CsCl chalcogenide glass of Φ30 mm was also prepared successfully, showing it of high potential for commercial applications. [ABSTRACT FROM AUTHOR]

Novel chalcogenide glasses of the pseudo-binary (100- x)Sb 2 S 3 - x PbI 2 system were synthesized by traditional melt-quenching method, and its glass-forming region was determined from x = 20 to 55 mol%. Compared to traditional sulfide glasses, the long-wave infrared (LWIR) cut-off edge of Sb 2 S 3 -PbI 2 glasses is extended up to 14 μm. The physical properties of these glasses, including their T g , Δ T (= T x − T g), Vickers hardness, density, and Abbe number, were characterized and analyzed using their compositional dependent Raman spectra. [SbI 3 ] structural units could promote the forming ability (Δ T) of the Sb 2 S 3 -PbI 2 glasses because of the broken connectivity of the network structure. The results of this research provide useful knowledge for developing novel LWIR chalcogenide glasses. [ABSTRACT FROM AUTHOR]

Applications of trivalent rare earth (RE3+)‐doped light sources in solid‐state laser technology, optical communications, biolabeling, and solar energy management have stimulated a growing demand for broadband emission with flexible tunability and high efficiency. Codoping is a conventional strategy for manipulating the photoluminescence of active RE3+ ions. However, energy transfer between sensitizers and activators usually induces nonradiative migration depletion that brings detrimental luminescent quenching. Here, a transparent framework is employed to assemble ordered RE3+‐doped emitters to extend the emission spectral range by extracting photons from a variety of RE3+ ions with sequential energy gradient. To block migration‐mediated depletion between different RE3+ ions, a nanoscopic heterogeneous architecture is constructed to spatially confine the RE3+ clusters via a "nanocrystals‐in‐glass composite" (NGC) structure. This bottom‐up strategy endows the obtained RE3+‐doped NGC with high emission intensity (nearly one order of magnitude enhancement) and broadband near‐infrared emission from 1300 to 1600 nm, which covers nearly the whole low‐loss optical communication window. Most crucially, NGC is a versatile approach to design tunable broadband emission for the potential applications in high‐performance photonic devices, which also provides new opportunities for engineering multifunctional materials by integration and manipulation of diverse functional building units in a nanoscopic region. A tunable broadband emission is demonstrated by assembly of ordered rare‐earth‐doped emitters with sequential energy gradient. Migration‐mediated energy quenching has been successfully suppressed by nanoscopic heterogeneous structures constructed in transparent nanocrystals‐in‐glass composites. This assembly strategy highlights the possibility to fabricate multifunctional materials by linking different building units with photonic, magnetic, and electronic properties in a transparent framework. [ABSTRACT FROM AUTHOR]