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The development of the new generation of smart near infrared (NIR) light sources is a problem demanding prompt solution with the increasing role of NIR spectroscopy in security, food, medical treatment, agriculture, and other fields. In this work, Cr3+ doped ANb2O6 (A = Zn/Mg) phosphors are successfully developed, which generate a NIR emission with a peak at 930 nm covering 750–1300 nm under excitation of 515 nm light. Thanks to the small Stokes shift, the internal quantum efficiency (IQE) values of the optimal samples of ZnNb2O6:Cr3+ and MgNb2O6:Cr3+ reach up to 70% and 62%, respectively. This ultra‐broadband NIR emission originates from the simultaneous occupation of [AO6] and [NbO6] octahedrons by Cr3+, which is confirmed by the excitation wavelength‐dependent emission spectra, low‐temperature photoluminescence spectra (77 K), time‐resolved photoluminescence (TRPL) spectra, and density functional theory (DFT) calculation. The thermal quenching mechanism of ANb2O6:Cr3+ (A = Zn/Mg) is revealed from the aspects of thermal cross and thermal ionization. Benefiting from the excellent performance of ANb2O6:Cr3+ (A = Zn/Mg) NIR phosphors, the combination of 520 nm LED chips, and as‐prepared phosphors demonstrate the dramatic potential applications in night vision, non‐destructive testing, biological tissue imaging, and spectral analysis. [ABSTRACT FROM AUTHOR]

Cr3+‐activated near‐infrared (NIR) phosphors are one of the most influential candidates for the new generation of intelligent NIR phosphor‐converted light‐emitting diode (pc‐LED) light sources. For spectral analysis, the broader the spectrum, the more useful information it contains. Herein, ultra‐broadband Cr‐activated Sc2O3 nanophosphors, which exhibit NIR ultra‐broadband from 650 to 1600 nm, are developed by the sol–gel method. This ultra‐broadband emission originates from the presence of Cr3+ and Cr4+, two luminescent centers confirmed by diffuse reflection spectra, electron paramagnetic resonance, time‐resolved photoluminescence spectra, and temperature‐dependent emission spectra. The nanophosphor exhibits excellent temperature‐sensing performance with SA = 4.102% K−1 and SR = 1.855% K−1. Co‐doping Yb3+ into Sc2O3 nanophosphors builds the Cr3+‐Yb3+‐Cr4+ model to bridge the spectral gap located at 1000 nm, forming a continuous NIR ultra‐broadband spectrum ranging from 650 to 1600 nm for the first time. Moreover, the introduction of Yb3+ improves the thermal stability of nanophosphors from 29.49% to 50.65% at 150 °C. The NIR transmission spectra of water, ethanol, and peanut oil demonstrate that Sc2O3:Cr3+‐Yb3+‐Cr4+ NIR nanophosphors favor potential applications in spectral analysis. The construction of a Cr3+‐Yb3+‐Cr4+ spectral bridge for realizing NIR ultra‐broadband phosphors based on cheap blue LEDs provides novel and effective insights. [ABSTRACT FROM AUTHOR]

Cr3+‐activated near‐infrared (NIR) phosphors have attracted wide attention owing to applications in phosphor‐converted light‐emitting diodes (pc‐LED) for spectroscopy. Because a broader spectrum covers more information to detect, the width of the spectrum is an important parameter to consider. Here, the blue LED excitable ultra‐broadband Cr3+‐activated LiInGeO4 phosphors, which exhibit unprecedented long‐wavelength NIR emission with a wide full‐width at half maximum (FWHM) of 305 nm, are developed. The overall emission tuning from 1165 to 875 nm with broadened FWHM from 305 to 508 nm is realized through designing continuous solid solution hosts of LiIn1−zSczGeO4/(LiIn)1−yMg2yGeO4 and finite solid solution hosts of (LiIn)1−yZn2yGeO4:Cr3+. The observation of such long‐wavelength NIR from Cr3+ not Cr4+ is studied and confirmed by electron paramagnetic resonance, X‐ray absorption near‐edge structure, and steady‐/transient‐state photoluminescence. The formation of finite solid solutions induces the change in the local structure of Cr3+ that ultimately leads to the observation of super broadband (FWHM = 508 nm) luminescence. The luminescence mechanism is discussed in this study. Finally, this study demonstrates that the as‐synthesized phosphors with tunable NIR luminescence can be well used in NIR pc‐LEDs for spectroscopy detection. [ABSTRACT FROM AUTHOR]