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Near‐infrared (NIR) phosphors converted light‐emitting diodes (NIR pc‐LEDs) are ideal NIR sources for versatile applications, which imply the practical significance in tailoring the emission of the NIR phosphors to enhance the performance for specific application. Herein, a paradigm of tailoring the emissions in a series of Cr3+‐doped phosphors to match the applications in NIR lighting, detection, and short‐wave infrared sources through combinatorial management of crystal‐field and energy transfer is presented. The emission band largely increases from 84 to 190 nm when the introduction of [MgO6]‐[GeO4] into Y3Ga5O12:0.08Cr3+ forms Y3MgxGa5‐2xGexO12:0.08Cr3+ through the substitution of [GaO6]‐[GaO4]. Such a large increase in width makes it suitable for near‐infrared lighting to near‐infrared detection. Moreover, the Yb3+, Nd3+ and Er3+ are doped to construct energy transfer with Cr3+, broadening the emission infrared region and enhanced thermal stability. An optimized Yb3+ emission dominates Y3Ga5O12:0.4Cr3+,Yb3+ phosphor has excellent thermal stability (129%@423 K) and is suitable for high‐power short‐wave infrared sources. The presented work not only provides a series of well‐performed NIR phosphors, but only lights up the avenue for designing the Cr3+ emission for specific application. [ABSTRACT FROM AUTHOR]

In this work, a series of BaSrGd4O8:xBi3+ blue phosphors was synthesized employing the high-temperature solid-state method. Phase purity of the samples was verified by X-ray diffraction and Rietveld refinement. Time-resolved photoluminescence spectra revealed the existence of two distinct Bi sites. Subsequent optimization of dopant types and doping levels in the batch led to an almost twofold increase in quantum efficiency. The introduction of Eu3+ into the phosphors facilitated the construction of an energy transfer pathway. As the concentration of Eu3+ was increased, the emission color changed from blue to purple and finally to red. In addition, the thermal stability and potential applications of the phosphors were extensively investigated. Finally, two WLED devices were successfully fabricated with color rendering indices of 96.27 and 92.18, and correlated color temperatures of 5198 and 2475 K. This underscores the prospective application of these phosphors in the field of high-quality warm WLEDs. [ABSTRACT FROM AUTHOR]

A novel apatite‐type SrMgY3(SiO4)3F was synthesized by a high‐temperature solid‐state reaction. The crystal structure was refined using powder X‐ray diffraction data. SrMgY3(SiO4)3F crystallizes in P63/m hexagonal space group with lattice parameters of a = b = 9.45270 Å, c = 6.77617 Å, and V = 524.357 Å3. The incorporation of the Ce3+ and Tb3+ ions into the matrix can generate bright blue and green lights under ultraviolet (UV) light excitation. The codoped Ce3+ and Tb3+ in SrMgY3(SiO4)3F can effectively improve green emission intensity and thermal stability through the energy transfer from the Ce3+ to Tb3+ ions. With the increase of Tb3+‐doping content, the luminescent color of phosphor changes from blue to cyan and finally to green. SrMgY3(SiO4)3F:0.06Ce3+,0.90Tb3+ phosphor exhibited intense green light emission with a quantum yield of 59.49% and good thermal stability, with an emission intensity at 150°C was 96% of that at 30°C. Finally, the prepared sample was coated on 365 nm UV chips to fabricate white light‐emitting diodes with a color rendering index of 82.6 and a correlated color temperature of 2912 K, demonstrating its potential for applications in display and lighting. [ABSTRACT FROM AUTHOR]

It is of significant importance to tailor the luminescent properties of Cr3+ ions as efficient near‐infrared (NIR) emitter for extended optical applications. Here, crystal field engineering is explored to tailor the luminescent properties of a Cr3+‐doped garnet, Lu2Ca1 ‐ xSrxAl4SiO12 (x = 0–1). As Ca2+ is substituted by Sr2+, the emission of Cr3+ becomes sharper with longer lifetime, indicating that the 2Eg→4A2g transition becomes dominant. More importantly, the thermal stability is greatly improved, as the emission intensity at 480 K increases from 83% to 111% of that at 300 K. Moreover, the efficiency of the energy transfer from the Cr3+ to Yb3+/Nd3+ increases from 60–70% to 80–90%. The intensity ratio of I810/I706 from the Lu2SrAl4SiO12:Cr3+,Nd3+ can be applied to thermometry, with the maximum relative sensitivity value of 1.43% K–1 at 303 K. Compared with the blue emission from light‐emitting diode (LED) chip, a clearer and more accurate imaging is established with NIR emission from Cr3+. Furthermore, the intensity ratio of the emissions from the Cr3+ and Yb3+ ions is applied to differentiate pork, chicken, and beef. These findings provide an avenue to optimize the thermal stability and energy transfer of Cr3+‐activated NIR emitters for the applications in thermometry and NIR‐LED. [ABSTRACT FROM AUTHOR]

Achieving emission peaks in the near‐infrared II regions (NIR II) and tunable near‐infrared (NIR) emission is still a huge challenge in the development of NIR phosphors. Here, a series of LiSc1‐yGayW2O8:Cr3+ phosphors are reported based on crystal engineering, whose luminescence can be tuned from NIR‐II to NIR I. LiScW2O8:Cr3+ possesses an ultra‐wide emission in the range of 850–1400 nm with peak at 1069 nm and a full width at half maximum (FWHM) of 225 nm and the main emission light is located in the NIR‐II region. Introducing Ga3+ into LiScW2O8:Cr3+ to form LiSc1‐yGayW2O8:Cr3+, the emission spectrum is blueshifted, which better aligns with the characteristic absorption lines of most functional groups. Additionally, the intensity of emission and thermal stability are also improved. The NIR phosphor‐converted light‐emitting diodes (pc‐LED) device is prepared by using the optimized LiSc0.5Ga0.5W2O8:0.12Cr3+ phosphor and green chip, and different characteristic absorptions are detected by measuring the NIR absorption of water and ethanol with the prepared pc‐LED as a radiation source. These results indicate that the ultra‐wide near‐infrared luminescence of LiSc1‐yGayW2O8:xCr3+ holds potential for applications in non‐destructive analysis. [ABSTRACT FROM AUTHOR]