properties, low cost, facile preparation and high defect tolerance. [1] Remarkable progress has been made, especially in terms of widespread applications spanning from solar cells, photodetectors, photocatalysts, and solid-state lasers to light-emitting diodes (LEDs). [2] In more recent years, owing to the exceptional luminescence properties, such as high brightness, color tunability, and intense absorption coefficient, lead halide perovskites have found promising potential applications as color converter for next-generation solid-state lightings and backlight displays. [3] Unfortunately, the intrinsic nature of poor stability and toxicity of lead halide perovskites are some serious issues to be tackled if the materials are to be used on a large scale. The chemical instability will severely restrict the lifespan of devices, and the accumulation of lead will cause serious environmental problems and fatal threat to human health. [4] Extensive efforts have been devoted to overcome the thorny challenges on the way to practical applications. To completely eliminate the potential danger of lead leakage, the simplest and practicable way is to replace it in the B site of ABX 3 with nontoxic isovalent metal ions. [5] As reasonable candidates, Ge 2+ and Sn 2+ ions are the first to come to mind for the substitution of Pb 2+ due to the same electronic configuration of ns 2 np 0 Lead halide perovskites have emerged as superstar semiconductors owing to their superior optoelectronic properties. However, the issues of chemical and thermodynamic instability and toxicity are yet to be resolved. Here, the non-and Bi 3+-doped all-inorganic lead-free perovskite derivatives are reported. Most remarkable is the successful extending of excitation of Cs 2 ZrCl 6 to match with the commercial near ultraviolet light-emitting diode chips via deliberate Bi 3+ aliovalent doping. The blue emission, contrary to self-trapped exciton (STE) emissions amply reported previously, originates from Bi 3+ ionoluminescence with a high photoluminescence quantum efficiency of 50%. The competition for harvesting electrons between STEs and Bi 3+ is studied in detail by steady-and transient-state fluorescence spectroscopy in combination with theoretical calculations. Surface grafting endows Cs 2 ZrCl 6 :Bi 3+ with a robust water-resistant core-shell-like structure and abiding emission. Surprisingly, the emission intensity even increases to 115.94% of the initial level after immersing in water for 2 h. The as-obtained phosphor enables the fabrication of a white light-emitting diode (w-LED), achieving CCT = 4179 K and Ra = 81.9. This work not only promotes the step toward development of leadfree, stable, and high-efficiency perovskite derivatives for the next-generation warm w-LEDs, but also reveals the structure-PL relationship.

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Multifunctional near-infrared emitting Cr3+-doped Mg4Ga8Ge2O20 particles with long persistent and photostimulated persistent luminescence, and photochromic properties.

A super-long-persistent phosphor Ba2SiO4:Eu2+,Ho3+ and photostimulable luminescence for optical information storage.

Broadband shortwave infrared (SWIR) light-emitting diodes (LEDs), capable of advancing the next-generation solid-state smart invisible lighting technology, have sparked tremendous interest and will launch ground-breaking spectroscopy and instrumental applications. Nevertheless, the device performance is still suppressed by the low quantum efficiency and limited emission bandwidth of the critical phosphor layer. Herein, we report a high-performance Ni2+-doped garnet solid-solution broadband SWIR emitter centered at ∼1450 nm with a large full-width at half-maximum of ∼300 nm, thereby fabricating, for the first time, a directly excited Ni2+-doped garnet solid-solution phosphor-converted broadband SWIR LED device. A synergetic enhancement strategy, adding a fluxing agent and a charge compensator simultaneously, is proposed to deliver a more than 20-fold increase of the SWIR emission intensity and nearly 2-fold improvement of the thermal quenching behavior. The site occupation and mechanism behind the synergetic enhancement strategy are elucidated by a combination of experimental study and theoretical calculation. A prototype of the SWIR LED with a radiation flux of 1.25 mW is fabricated and utilized as an invisible SWIR light source to demonstrate the SWIR spectroscopy applications. This work not only opens a window to explore novel broadband SWIR phosphors but also provides a synergetic strategy to remarkably improve the performance of artificial SWIR LED light sources.

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Optically stimulated luminescence (OSL) materials, enabling energy storage by capturing of charge carriers and then the energy conversion to light via photostimulation, can find many advanced applications in various fields, spanning from radiation dosimetry, optical data storage and security, environmental monitoring, biomedicine, clinical diagnostic, to archaeology and geology. At present, there are some blocks, including the development of nanocrystallization approaches, the tailoring of optical transitions, the control of trap distribution, and the understanding of OSL mechanisms, on the road to the exploration of OSL materials. This review gives an overview of the design, preparation, characterization, optimization, application, mechanism, and prospect of OSL materials. A short introduction of the fundamental principle and history of OSL materials is presented, followed by a summary of preparation and design methods, and a survey of OSL materials reported to date. The trap engineering, mechanism, and study methodologies of OSL are summarized, after which the widespread applications of OSL materials, in traditional and newly emerging fields, are reviewed. Finally, the merits and drawbacks of the OSL materials according to the relevant reports currently available are examined. The challenges and outlooks are highlighted and discussed in terms of five important aspects that merit future research.