efficiency,low-energy consumption, long lifetime, and environmental compatibility, and so on. [1][2][3] The common w-LEDs devices are fabricated via two combination strategies: 1) blue LED chip and yellow phosphor; 2) nearultraviolet (n-UV) LED chip and tricolor phosphors. [4,5] No matter for which fabrication methods, the development of red phosphor is crucial to improve the lighting quality and tune corrected color temperature of w-LEDs. [6,7] To date, many researchers have focused on exploring highly efficient red phosphors. Although Eu 2+ -doped nitride phosphors such as CaAlSiN 3 :Eu 2+ and Sr 2 Si 5 N 8 :Eu 2+[8-10] show high quantum yield (QY > 90%) and high thermal quenching temperature (>600 K), the harsh preparation conditions (high pressure ≥ 0.9-2.5 MPa; high temperature ≥1700-200 °C) and deepred emission position (beyond 650 nm) limit the large-scale application in indoor lighting. Eu 3+ -doped inorganic compounds are typical red-emitting phosphors due to the (4f 6 ) 5 D 0 → (4f 6 ) 7 F J spin-and parity-forbidden transition, [11,12] but it is hardly utilized in w-LEDs applications owing to the linearly narrow excitation and emission. [13,14] Mn 4+ has been considered as the promising red-emitting activator Nowadays, red phosphor plays a key role in improving the lighting quality and color rendering index of phosphor-converted white light emitting diodes (w-LEDs). However, the development of thermally stable and highly efficient red phosphor is still a pivotal challenge. Herein, a new strategy to design antithermal-quenching red emission in Eu 3+ , Mn 4+ -codoped phosphors is proposed.

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Near-infrared light-emitting diodes (NIR-LEDs) are potential candidates in food composition analysis, temperature and security monitoring, biometrics, and medical applications. To realize the above objectives, the development of NIR-emitting phosphors is urgently required. Herein, a novel NIR emission is successfully achieved in Bi3+-activated XAl12O19 (X = Ba, Sr, Ca) compounds by constructing the selective site occupation of Bi3+ in Al3+ polyhedra with small coordination number. The designed phosphors exhibit broad-band NIR emission of Bi3+ from 600 to 1000 nm. Interestingly, a broad photoluminescence control from blue to red is also achieved by just changing the sintering atmosphere. The blue emission of Bi3+ should be assigned to the prior occupation in X2+ sites and the existence of oxygen vacancy. This work not only provides a novel insight to develop NIR-emitting Bi3+-activated phosphors but also helps to reveal the underlying NIR luminescence mechanism of Bi3+ in inorganic compounds.

Highly efficient green/yellowish‐orange phosphors with low thermal quenching behavior are urgently required to improve the luminescence efficiency, color stability, and color rendering of phosphor‐converted white light emitting diodes (w‐LEDs). Herein, a novel green Cs2BaP2O7:0.01Eu2+ phosphor with high luminescence efficiency (82.7%) and thermal quenching behavior (92.5% at 423 K) is reported. Besides, a further luminescence improvement in the quantum yield (98.9%) and thermal quenching resistance (120% at 448 K) is successfully achieved in green/yellowish‐orange color‐tunable Cs2MP2O7:0.01Eu2+ (M = Ba, Sr, and Ca) phosphors. Surprisingly, these green/yellowish‐orange Cs2MP2O7:0.01Eu2+ (M = Ba, Sr, and Ca) phosphors even have a prior advantage over the commercial green β‐SiAlON:Eu2+ and yellow YAG:Ce3+ phosphors. The corresponding spectral adjustment and thermal stability mechanisms are revealed, related to the optimization of local lattice symmetry. The prototype w‐LEDs exhibit warm white light with CIE color coordinate at (0.337, 0.322). The color rendering index, corrected color temperature, and luminescence efficiency can reach 92.6, 4044 K, and 152.56 lm W−1, respectively. In general, the as‐reported green/yellowish‐orange Eu2+‐doped pyrophosphate phosphors are promising candidates in the future high‐quality w‐LEDs applications. The proposal of local lattice symmetry modulation can provide a new approach to exploit novel phosphors with excellent thermal quenching resistance.

Thermal quenching (TQ) of phosphor is one of the biggest challenges to develop high‐quality white light‐emitting diodes (w‐LEDs). Herein, an anti‐thermal‐quenching (anti‐TQ) property in cyan‐emitting Ba2ZnGe2O7:Bi3+ phosphor is reported. At 150 °C, its emission intensity increases to 114% of the original intensity at 25 °C. Especially, the integrated emission intensity reaches 138%, 148%, and 134% at 150, 200, and 250 °C, respectively, by artificially creating zinc and oxygen vacancy defect. The anti‐TQ phenomenon is mainly attributed to high structure rigidity and strong ability to compensate emission loss during thermal generation process. Thermal‐induced emission compensation mainly stems from self‐oxidization behavior of Bi2+ in zinc vacancy and the presence of oxygen vacancy defect. Oxygen vacancy is induced by native zinc vacancy and charge imbalance between Bi3+ and Ba2+ ions. The strategy to create oxygen vacancy defect and design self‐oxidization process of Bi opens a new insight to exploit anti‐TQ phosphors for high‐quality w‐LEDs applications.