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Embedding all-inorganic CsPbX3 (X = Cl, Br, and I) perovskite nanocrystals (PNCs) into glass matrixes overcomes the instability of PNCs. However, there is still a significant need to enhance the photoluminescence properties of CsPbX3 PNC glasses for optoelectronic applications. Currently, there are few strategies to modulate the photoluminescence (PL) of CsPbX3 PNC glasses due to a lack of understanding regarding the precipitation and PL mechanism of PNCs in glass matrixes. In this work, effective strategies were proposed to enhance visible PL by using Bi ions as fluorescent probes and structural modifiers. The addition of Bi ions promoted the precipitation of CsPbX3 PNCs in glasses, and increased the photoluminescence quantum efficiency (PLQE) by 5-fold. Various characterisation studies demonstrated that Bi ions effectively compensated for structural defects and transferred energy to CsPbX3 PNCs, thereby suppressing non-radiative transitions. Furthermore, high-purity green- and red light emitting diodes (LEDs) were successfully fabricated by combining CsPbX3:Bi2O3 PNC glasses with blue LED chips. Clear fluorescence imaging was achieved using a miniaturised fluorescence detector with the green LED as an excitation source. This work provides a powerful strategy for designing highly efficient PNC glasses with potential applications in lighting, displays and bioimaging. [ABSTRACT FROM AUTHOR]

Multi‐mode mechanoluminescence (ML) materials are have applications such as anti‐counterfeiting, stress sensing, and information security. There is limited general consensuses on the luminescent mechanisms, even though exploring ML mechanism based on defects has shown significance in further studies exploring both ML materials design and application. Here, a deep‐red to near‐infrared (NIR) ML material is reported in a Mn2+‐activated double perovskite‐type compound (CaZnGe2O6: Mn2+). The abundant lattice sites within the crystal structure have enabled Mn2+ doping and defects. Two different photoluminescence (PL) emission bands peaked at 536 and 676 nm from 4T1(4G)→6A1(6S) are observed, which are attributed to the substitution of Zn2+ and Ca2+ sites by Mn2+, respectively. Hence, tunable emissions from green to red are realized in single Mn2+ doping, which can be further regulated by varying the Mn2+ concentration. Electrons and holes are captured by cation and anion defects (VZn′′$V_{{\mathrm{Zn}}}^{\prime \prime }$ and VCa′′$V_{{\mathrm{Ca}}}^{\prime \prime }$, VO••$V_{\mathrm{O}}^{ \bullet \bullet }$, vacancy of Zn, Ca and O ions), followed by the combination of such carriers to transfer energy to the Mn2+ 3d states to produce ML/persistent luminescence (PersL) under mechanical/thermal stimuli. Proof‐of‐concept applications in multi‐mode anti‐counterfeiting, temperature sensing, and X‐ray imaging fields are demonstrated. These results will deepen the understanding of single Mn2+‐doped multi‐stimulus‐responsive ML materials, inspiring the development of more high‐performance ML phosphors for practical applications. [ABSTRACT FROM AUTHOR]

Bismuth (Bi)-doped glasses with broadband near-infrared (NIR) emission have been drawing increasing interest due to their potential applications in tunable fiber lasers and broadband optical amplifiers. Yet, the realization of highly efficient and ultra-broadband Bi NIR emission covering the whole telecommunication window remains a daunting challenge. Here, via rationally controlling the content of Al2O3 to control the local environment and structural defect states around the Bi NIR active centers (BACs), various luminescence centers can coexist stably in a glass matrix. Consequently, tunable ultra-broadband multi-band NIR emission with four emission bands at ∼924, ∼1154, ∼1265, and ∼1516 nm was achieved in a Bi-doped germanate glass under single wavelength excitation. More importantly, such ultra-broadband multi-band Bi NIR emission with excellent thermal stability can be well retained after the glass was drawn into an optical fiber by a rod-in-tube method. The fibers show an obvious broadband ASE spectrum spanning a range of 1000–1600 nm. This work is helpful for understanding the mechanism of Bi NIR emission and offers a simple and feasible method for developing novel photonic devices with ultra-broadband Bi NIR emission. [ABSTRACT FROM AUTHOR]

Mechanical luminescence (ML) is the conversion of mechanical energy into light energy when a material is subjected to a force. It is challenging to develop ML materials with tunable luminescent properties by single ion doping, which have broad application prospects in the fields of stress sensing and dynamic signature anticounterfeiting. In this study, a Pr3+ doped Sr2Ga2GeO7 tunable ML material is reported. Due to the traps resulting from unequal substitution of Pr3+–Sr2+ in [SrO6] heptahedra, the deep/shallow traps redistribution occurs towards a multicolor ML from red to green. In addition, even after continuous friction sliding force (15 N), the ML intensities can be recovered after ultraviolet pre‐irradiation, indicating that Sr2Ga2GeO7: Pr3+ has excellent ML emission stability. Based on thermoluminescence analysis, potential PersL and ML mechanisms are further elaborated by a lattice engineering (trap regulation) strategy. In all, the development of single‐ion doped multicolor ML materials may have crucial research value and show a variety of potential applications in the fields of anticounterfeiting and information encryption. [ABSTRACT FROM AUTHOR]

The ability to locate and quantify large strains will significantly improve the real‐world application scenario of flexible and stretchable strain sensors. However, current methods for implementing stretchable distributed strain sensing still face challenges such as complicated demodulation, multisensor crosstalk, and high power consumption. Herein, a self‐powered and stretchable optical fiber strain sensor is reported with distributed sensing capability based on mechanoluminescent optical fiber, where mechanoluminescent phosphors with different emission color light are discretely integrated onto the outer cladding of the elastomer optical fiber. Based on the wavelength coding technique and time‐domain filtering comparison method, the capability of strain magnitude quantification (10–60%) and strain location identification together in a single stretchable optical fiber is successfully realized, even at multiple positions simultaneously in the strain‐applied situation. Moreover, this stretchable optical fiber strain sensor shows insensitivity to bending, compression, and temperature disturbances and outstanding durability (>8000 cycles). Due to the excellent light confinement of the elastomer optical fiber, demonstrations such as bright‐field measurement, saline water operation, and wearable glove application exhibit its potential as a promising technology for future self‐powered distributed optical sensing systems. [ABSTRACT FROM AUTHOR]

Demands are increasing for ultrashort pulse laser in industrial applications, where the gain bandwidth of most optical fiber material is not wide enough, and developing a wide bandwidth gain medium is challenging. Glass–ceramic fibers containing Nd3+/Yb3+ co‐doped YCa4O(BO3)3 nanocrystals were fabricated by the molten core method and successive heat treatment. After a careful heat treatment, Nd3+/Yb3+ co‐doped YCa4O(BO3)3 nanocrystals were precipitated in the fiber core. Enhanced broadband near‐infrared (NIR) emission from 850 to 1150 nm (bandwidth: ∼252 nm) was obtained in the glass–ceramic fiber compared to that of precursor fiber. These results suggest that the Nd3+/Yb3+ glass–ceramic fibers are promising for broadband NIR optical amplifications and lasers. [ABSTRACT FROM AUTHOR]

Mechanoluminescence (ML) materials have found potential applications in information storage, anti‐counterfeiting, and stress sensing. Conventional stress sensing based on absolute ML intensity is prone to significant mistakes owing to the unpredictability of measurement surroundings. However, implementing a ratiometric ML sensing technique may considerably ameliorate this issue. In this study, a single activator‐doped gallate material (LiGa5O8:Pr3+) is proposed to determine the relationship between the ML intensity and the change in local positional symmetry that occurs when the material is subjected to stress. The sensing reliability of the ML intensity ratio under different factors (Force; Content; Thickness and Materials) is systematically analyzed, where the factor that has the greatest effect on the proportional ML is the concentration, with the ML intensity asymmetry ratio decreasing from 1.868 to 1.300 varying concentration at constant stress. The colour‐resolved visualization of stress sensing is further realized, which opens a new path for a ratiometric ML‐based strategy to improve the reliability of stress sensing. [ABSTRACT FROM AUTHOR]