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In recent years, broadband near-infrared (NIR) spectroscopy has attracted widespread research attention. However, the development of broadband NIR-emitting phosphors with superior thermal stability under excitation by near-ultraviolet or blue LED chips remains a challenge. Furthermore, silicon nanostructured materials exhibit unique photoelectric properties and environmentally friendly characteristics. While the study of crystalline silicon nanoparticles has garnered significant attention, research on amorphous structures remains limited. In this study, we synthesized amorphous silicon nanoparticles (a-Si NPs) with a wide near-infrared emission ranging from 600 nm to 1000 nm, achieved through a sol–gel derived polymer and a subsequent heat treatment process. The surface of a-Si NPs was effectively passivated by secondary annealing, resulting in enhanced near-infrared emission. Additionally, these nanoparticles displayed a NIR fluorescence emission peak at 812 nm with a full width at half maximum (FWHM) of 169 nm, alongside remarkable thermal stability. Consequently, the integrated NIR pc-LED device demonstrated outstanding night vision imaging capabilities. As an accurate fingerprint developer, it provides enhanced imaging on various substrates to reveal detailed features. The findings suggest that the a-Si NP phosphor has considerable potential for applications in night vision imaging and could make significant contributions to fingerprint detection technology. This research provides a valuable reference for the exploitation and further development of amorphous silicon-based optical materials. [ABSTRACT FROM AUTHOR]

Phosphors play an extremely important role in solid-state lighting and full-color displays. Recently, it has been observed that their properties can be extensively utilized in the field of anti-counterfeiting. For the study of innovative anti-counterfeiting materials, the selection of high-quality matrix materials is indispensable. In this work, green AlN:Eu2+ phosphors are synthesized by the direct nitriding method, and their physical structure, micro-morphology, elemental composition, and photoluminescence properties are systematically investigated at different synthesis temperatures and doping concentrations. The results show that the peak emission of AlN:0.05Eu2+ occurs at 525 nm at a synthesis temperature of 1400 °C, and the fluorescence intensity retains 53.5% of its room temperature value when the test temperature is increased to 110 °C. The synthesized phosphors are dispersed in thermoplastic polyurethane (TPU) to create a UV-excited, flexible anti-counterfeiting film. The AlN:Eu2+@TPU anti-counterfeiting film exhibits excellent light transmission, flexibility, stretchability, and water resistance. When a current of 50 mA is applied, the green LED encapsulated with AlN exhibits high color purity. The CIE coordinates of the white LED are (0.32, 0.34), with a relevant color temperature (CCT) of 5727 K and a color rendering index (Ra) of 85.9. Overall, the results suggest that AlN:Eu2+ phosphors possess significant potential for realizing multidimensional applications in lighting displays and anti-counterfeiting. [ABSTRACT FROM AUTHOR]

The crystallization behavior of halide perovskites is of great significance. Fractal structures, featured by self-similarity between local morphology and global structures, have consistently captivated scientists' interest across diverse disciplines. In this study, we realized the fractal patterns in lead-free zero-dimensional (0D) Cs2InBr5(H2O) perovskites. By depositing saturated precursor droplets on silicon or glass substrates, we initiated nucleation and crystallization of 0D Cs2InBr5(H2O) crystals on the liquid's upper surface. As the solution evaporated, the remaining high-concentration solution formed self-similar fractal patterns beneath the Cs2InBr5(H2O) crystals. This anisotropic growth mechanism imparted a unique self-assembly behavior to 0D Cs2InBr5(H2O). Additionally, X-ray diffraction results confirmed distinct preferential orientations of the fractal patterns. The findings of this work provide valuable insights into the controlled crystallization behavior of lead-free perovskites and inspire further exploration of novel optoelectronic properties arising from such a unique fractal pattern. [ABSTRACT FROM AUTHOR]

Homogeneous colloidal silicon nanoparticles (Si NPs) were synthesized at ambient temperatures. With the incorporation of poly-(vinyl alcohol) (PVA), the absolute photoluminescence quantum yield (APLQY) and photochromic stability of the fluorescent colloid (p-Si NPs) were significantly enhanced compared to Si NPs. In the absence of additional high-temperature treatments or doped fluorophores, colloid p-Si NPs exhibit blue-green luminescence under ultraviolet excitation. Subsequently, the highly dispersed p-Si NPs solution underwent heat treatment, resulting in a suitable viscosity for direct screen printing. The printed pattern appears transparent under natural light and blue-green under ultraviolet light, showing good invisibility. These patterns possess notable characteristics, including high adhesion, uniformity, stain resistance, and excellent stability. Consequently, they can be efficiently developed for anticounterfeiting labels and printing inks. Notably, the ink also has the characteristics of low toxicity and substantial biocompatibility, offering promising avenues for the synthesis and application of environmentally friendly benign nano anticounterfeiting ink. [ABSTRACT FROM AUTHOR]

Na(Nb1−xTax)O3 binary solid‐solution ceramics with high quality were fabricated by conventional solid‐state sintering routes for improving the electric(E)‐field‐induced irreversible polarization and transition behaviors of NaNbO3. The studied results confirm that this binary solid‐solution ceramics exhibit orthorhombic Pbcm space group companying with reduced unit‐cell volume at x ≤ 0.4, and orthorhombic Pbnm space group at x = 0.5. As the Ta5+ content increases in the binary solid‐solutions, the E‐field‐induced irreversible antiferroelectric → ferroelectric (AFE → FE) transition becomes reversible at x ≥ 0.2, giving rise to double‐polarization hysteresis; the key E‐fields triggering both irreversible and reversible transitions (EF) increase in general. In particular, the E‐field‐induced FE phase at x = 0.15 is unstable upon unloading E‐field to zero, which can return to AFE phase with time lapse. At x = 0.5, the Curie temperature (TC) of AFE shifts to below room temperature, but E‐field‐induced reversible transition is still observed, which results in a nonlinear polarization with the lowest hysteresis and contributes to the largest energy‐storage density. This transition is not due to the AFE ↔ FE transition but rather to the order ↔ disorder behavior of polar clusters or/and nanoregions within nonpolar Pbnm structure matrix. [ABSTRACT FROM AUTHOR]

Very recently, metal–organic framework (MOF)-based derived oxides demonstrated excellent sensing performance to NO2. However, the study on the enhancement of gas-sensing characteristics by near-infrared (NIR) light for MOF-based derived oxides is still limited. In this work, we introduced the synthesis of MOF-derived SnO2 nanosheets by solvothermal and annealing processes. The structural composition and microstructure of SnO2 nanosheets were studied by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Brunauer–Emmett–Teller. The derived SnO2 nanosheet-based gas sensor has an extremely low theoretical detection limit to NO2 (45 ppb), ultrahigh response (1500 to 100 ppm), outstanding stability, and ideal selectivity. Furthermore, NIR illumination shortens the SnO2 sensor's NO2 adsorption/desorption process. Moreover, we also proposed that NIR-excited photoelectrons were instrumental in optimizing the NO2 gas-sensing performance of SnO2 sensors. Therefore, MOF-based SnO2 sensors are attractive for high response and rapid detection of NO2 at low operating temperatures and are expected to be widely used in the preparation of NIR-enhanced NO2 gas monitoring sensors. [ABSTRACT FROM AUTHOR]

Dopamine (DA) is a small biological molecule that causes a variety of diseases when its concentration is abnormal. Therefore, highly sensitive detection of DA is very important for the development of biomedicine and monitoring of human health. Herein, we prepared a carbon cloth (CC)/Ti3C2Tx/NiCoP composite as a highly sensitive electrochemical sensor for DA detection. Porous NiCoP was grown on the surface of CC and Ti3C2Tx by hydrothermal and phosphating treatments. The composite integrated the advantages of large specific surface area of zero-dimensional NiCoP quantum dots, rich electrochemical active sites of one-dimensional porous NiCoP nanowires, hydrophilicity of two-dimensional Ti3C2Tx nanosheets, and high conductivity of three-dimensional CC substrates. The sensor has high sensitivity (31.4101 μA μM–1 cm–2), wide detection range (0.17–784.55 μM), low detection limit (0.18 nM), elevated stability, and anti-interference ability. By analyzing the conductivity, hydrophilicity, and electrochemically active surface area of the CC/Ti3C2Tx/NiCoP composite, the reasons for its excellent performances are revealed for DA detection. At present, the research on NiCoP mainly focuses on hydrogen evolution, oxygen evolution, and supercapacitor. This research provides a regulatory strategy for the application of phosphide materials in sensors. [ABSTRACT FROM AUTHOR]

The SnO2-based family is a traditional but important gas-sensitive material. However, the requirement for high working temperature limits its practical application. Much work has been done to explore ways to improve its gas-sensing performance at room temperature (RT). For this report, SnO2, SnO, and SnO/SnO2 heterojunction was successfully synthesized by a facile hydrothermal combined with subsequent calcination. Pure SnO2 requires a high operating temperature (145 °C), while SnO/SnO2 heterojunction exhibits an excellent performance for sensing NO2 at RT. Moreover, SnO/SnO2 exhibits a fast response, of 32 s, to 50 ppm NO2 at RT (27 °C), which is much faster than that of SnO (139 s). The superior sensing properties of SnO/SnO2 heterojunction are attributed to the unique hierarchical structures, large number of adsorption sites, and enhanced electron transport. Our results show that SnO/SnO2 heterojunction can be used as a promising high-performance NO2 sensitive material at RT. [ABSTRACT FROM AUTHOR]

AgNbO3 exhibits "peculiar" anti-/ferroelectricity and narrow bandgap semi-conductivity that lead to active responses to different types of external stimuli, including electric fields, light and mechanical forces. Some of these unique properties are also mutually coupled and could be suited for the development of multifunctional devices for a broad range of applications, including dielectric, piezoelectric, high-power energy storage/conversion, photocatalytic and photovoltaic devices. In this review, recent studies of AgNbO3 and AgNbO3-based materials are summarized. The main scope is to establish the correlations between chemical composition, synthesis conditions, structure, and properties, with an improved understanding of the phase transformations taking place in the three so called "M" phases, to ultimately provide guidance on the materials development in two key sectors: high-power energy storage and photocatalysis. Finally, current challenges in multifunctional applications and future research directions are summarized. [ABSTRACT FROM AUTHOR]

White light-emitting diodes (WLEDs) possess the advantages of environmental friendliness, long lifetime, and energy saving. Recently, metal–organic frameworks (MOFs) have become one of the hot candidates for LEDs. However, the tunable color and thermal stability of MOFs are urgent problems for their actual applications. In this work, Ln-MOFs (Ln = Eu, Tb) were synthesized by a facile wet chemical route. A series of Ln-MOFs phosphors with tunable luminescence color showed potential applications in white LEDs. The emission color of the phosphors can be easily modulated by changing the molar ratio of the raw materials. The luminescence intensities of Ln-MOFs retained over 90.6% of the initial value, showing excellent thermal stability of Ln-MOFs. In order to explore the potential applications of Ln-MOFs in WLEDs, we mixed them with two kinds of blue phosphors and packaged them to obtain WLEDs. The CIE coordinates of both were (0.31, 0.33) and (0.31, 0.34), which were able to achieve white light emission. The peak shape and peak position in the EL spectrum of the WLEDs device remained stable when increasing the applied current of the device. Meanwhile, the white light with excellent color quality and visual performance was achieved. The results show that Ln-MOFs are potential materials for white light LED, and provide a novel idea for the application of Ln-MOFs materials in the luminescence field. [ABSTRACT FROM AUTHOR]

Surface microstructure regulation is an effective way to enhance the performance of sensing materials. Here, a hierarchical and flexible Brussels sprout-like Ni–Co(OH)2/rGO/carbon cloth (CC) composite was constructed by optimizing the morphology of Ni–Co(OH)2 microspheres and the addition amount of rGO. This sensor shows excellent reproducibility, high selectivity, and good stability. It shows a high sensitivity of 3.7391 mA mM−1 cm−2 in the 0.0388–124.0436 mM line detection range for H2O2 and 1.8457 mA mM−1 cm−2 in the 0.0300–2.0000 mM line detection range for glucose. The low limits of detection for H2O2 and glucose are 2.316 nM and 0.115 μM, respectively. The excellent electrochemical performance of the Ni–Co(OH)2/rGO/CC composite is attributed to its unique Brussels sprout-like microstructure. By studying the electrical conductivity, electrochemical active surface area, and hydrophilic–hydrophobic surfaces of the Ni–Co(OH)2/rGO/CC composite, the structure–performance relationship between the microstructure and sensing performance of the composite was further clarified. Moreover, the mechanism of CC, rGO, and the Ni–Co(OH)2 ternary composite in the sensing process is proposed. This study provides a new strategy for the construction of flexible wearable electrodes with high sensitivity. [ABSTRACT FROM AUTHOR]

Unraveling the morphology of the sensing material is of paramount in realizing the better sensitivity. For this purpose, the Bi2Ti2O7:Yb3+/Er3+ nanofibers (0:1, 4:1, 8:1, 15:1, 20:1) and nanoparticles were synthesized via an electrospinning and sol–gel route, respectively. Subsequently, the temperature sensing properties based on the fluorescence intensity ration were studied within Bi2Ti2O7:Yb3+/Er3+ nanofibers and particles in the range of 298–538 K. The maximum relative sensitivity value was 1.53% at 298 K for Bi2Ti2O7:Yb3+/Er3+ (4:1) nanofibers. As was expected, Bi2Ti2O7:Yb3+/Er3+ nanofibers demonstrated an enhanced temperature sensitivity than that of the individual nanoparticles, exhibiting the champion values among all the reported Yb–Er pairs. To exploit the potential for practical application, the Bi2Ti2O7:Yb3+/Er3+ nanofibers were utilized to measure the surface temperature of a heating object. An improved surface temperature resolution was realized compare with the infrared thermal camera. All the presented results confirmed that the novel upconversion Bi2Ti2O7:Yb3+/Er3+ nanofibers could be an outstanding candidate for temperature sensors. Our work has proven to be a reliable alternative for exploring contactless temperature sensing at a higher resolution. [ABSTRACT FROM AUTHOR]

Improving the stability of all‐inorganic halide perovskite nanocrystals has become an urgent task that cannot be ignored in practical applications. Lead halide perovskite CsPbX3 (X = Br, I, Cl) compounds are considered as the potential materials for next‐generation light‐emitting devices due to their superior optical properties. However, they are threatened by thermal degradation and atmospheric moisture. In order to better solve this practical problem, CsPbBr3 quantum dots (QDs) and CsPbBr3@Cs4PbBr6 nanocrystals (NCs) are tested under heating and cooling cycles, and the photoluminescence (PL) intensity loss of different perovskite materials at high temperatures is investigated. In addition, a thermoplastic polyurethane encapsulation strategy is proposed to improve their properties of thermal degradation and moisture resistance. This inexpensive and convenient method not only greatly reduces the PL intensity loss, but also shows excellent PL performance even in water. The encapsulated material has both flexible and elastic properties, which paves the way for the next commercial processing of all inorganic perovskite materials. [ABSTRACT FROM AUTHOR]

The piezospectroscopic (PS) effect was studied in an intergrowth bismuth layer-structure ferroelectric ceramic Bi5TiNbWO15 according to a micro-Raman spectroscopic evaluation. By using a ball-on-ring flexure configuration, a biaxial stress was generated in a Bi5TiNbWO15 plate-like specimen and in situ collected Raman spectra were acquired and analyzed under several loading conditions. As the observed spectral line contained signals arising from the whole illuminated in-depth region, the laser probe information was deconvoluted (by means of an in-depth probe response function obtained according to the defocusing method) in order to deduce biaxial PS coefficients for the three Raman bands of Bi5TiNbWO15 located at 763, 857, and 886 cm-1, respectively. The biaxial PS coefficients of these bands were derived to be -1.74±0.16, -2.51±0.16, and -2.64±0.31 cm-1/GPa, respectively, and should be referred to the c axis of the Bi5TiNbWO15 crystal. [ABSTRACT FROM AUTHOR]

Layered double hydroxide (LDH)-based catalysts have emerged as one of the most promising catalysts due to their unique layered structure, compositional flexibility, low cost, and easy synthesis. Herein, NiMn-LDH was in situ incorporated with carbon black (CB) via a facile hydrothermal method, and the morphology of the LDHs tended to be small-sized flaky-like from large bulk flower-like with the increasing amount of CB. The fabricated 50CB/NiMn-LDH cathode tended to induce the poorly crystalline film–like Li2O2 to form, indicating the significant effect of NiMn-LDH flake on the surface redox reaction. The lithium-oxygen (Li-O2) battery with 50CB/NiMn-LDH cathode exhibited improved capacity output (5684 vs 2682 mAh g−1), low overpotential (1.49 vs 1.62 V), and stable cyclability (35th vs 15th). The present synthetic strategy is very simple and low cost and can be easily extended to other LDH-based materials with significant effect. [ABSTRACT FROM AUTHOR]

Spectrally resolved cathodoluminescence measurements of Bi5-xLaxTiNbWO15 (x=0–1.50) ceramics at room temperature showed three distinct luminescence bands located at about 380, 502, and 660 nm, respectively, which were tentatively assigned to F+ center, oxygen vacancy-related defect and octahedron structure-related luminescence center, respectively. These assignments could be made in light of electron irradiation experiments with different exposure times. Bands related to oxygen vacancies were clearly enhanced by lanthanum doping, indicating that charge compensation occurred by the substitution of Bi for La3+ in perovskitelike structured intergrowth ferroelectrics. We observed that, for contents of La3+ x>0.75, La3+ ions entered the [Bi2O2]2+ layer according to a doping mechanism which is briefly discussed in this letter. [ABSTRACT FROM AUTHOR]