Near-infrared (NIR) fluorescence imaging technique is garnering increasing research attention due to various advantages. However, most NIR fluorescent probes still suffer from a false signals problem owing to their instability in real application. Especially in a pathological environment, many NIR probes can be easily destroyed due to the excessive generation of highly reactive species and causing a distorted false signal. Herein, we proposed an approach for developing a new stable NIR dye platform with an optically tunable group to eliminate false signals using the combination of dyes screening and rational design strategy. The conception is validated by the construction of two high-fidelity NIR fluorescent probes (NIR-LAP and NIR-ONOO − ) sensing leucine aminopeptidase (LAP) and peroxynitrite (ONOO − ), the markers of hepatotoxicity. These probes (NIR-LAP and NIR-ONOO − ) were demonstrated to sensitively and accurately monitor LAP and ONOO − (detection limit: 80 mU/L for LAP and 90 nM for ONOO − ), thereby allowing one to precisely evaluate drug-induced hepatotoxicity. In addition, based on the fluctuation of LAP, the therapeutic efficacy of six hepatoprotective medicines for acetaminophen-induced hepatotoxicity was analyzed in vivo. We anticipate the high-fidelity NIR dye platform with an optically tunable group could provide a convenient and efficient tool for the development of future probes applied in the pathological environment.

Bismuth ion is an excellent activator and sensitizer for luminescent materials, which has been extensively studied during the recent decades. Bi3+‐doped phosphors have received considerable attention for their abundant emission colors covering the whole visible light region under ultraviolet (UV) and near ultraviolet (n‐UV) excitation, in flexible crystal structures. These phosphor materials have demonstrated potential applications in solid‐state lighting, display, biomedical, and optical sensing. Herein, the recent advances in the structure design and photoluminescence properties of Bi3+‐doped phosphors together with their white light emitting diode (WLED) applications are reviewed. The design strategies for crystal structure and the discovery of typical phosphors are systematically summarized, and the luminescent properties of Bi3+ can be effectively regulated by these strategies. Then, the design of polychromatic Bi3+‐doped phosphors produced by different doping ions is described, which in turn can adjust the emission colors and realize a single‐component white‐light emission. This review will promote researches on the discovery of new Bi3+‐doped phosphor materials, and the design strategies could provide an extensive guidance for the discovery and preparation of high‐efficient phosphors with color‐tunable emission including white‐emission for WLEDs in the future. Additionally, research progress of Bi3+‐doped perovskite and Bi2+‐doped phosphor materials is briefly elucidated.

Red phosphor materials play a key role in improving the lighting and backlit display quality of phosphor-converted white light-emitting diodes (pc-WLEDs). However, the development of a red phosphor with simultaneous high efficiency, excellent thermal stability and high colour purity is still a challenge. In this work, unique non-concentration quenching in solid-solution Cs3Gd1 − xGe3O9:xEu3+ (CGGO:xEu3+) (x = 0.1–1.0) phosphors is successfully developed to achieve a highly efficient red-emitting Cs3EuGe3O9 (CEGO) phosphor. Under the optimal 464 nm blue light excitation, CEGO shows a strong red emission at 611 nm with a high colour purity of 95.07% and a high internal quantum efficiency of 94%. Impressively, this red-emitting CEGO phosphor exhibits a better thermal stability at higher temperatures (175–250 °C, >90%) than typical red K2SiF6:Mn4+ and Y2O3:Eu3+ phosphors, and has a remarkable volumetric negative thermal expansion (coefficient of thermal expansion, α = −5.06 × 10−5/°C, 25–250 °C). By employing this red CEGO phosphor, a fabricated pc-WLED emits warm white light with colour coordinates (0.364, 0.383), a high colour rendering index (CRI = 89.7), and a low colour coordinate temperature (CCT = 4508 K). These results indicate that this highly efficient red-emitting phosphor has great potential as a red component for pc-WLEDs, opening a new perspective for developing new phosphor materials.