Cr3+‐activated near‐infrared (NIR) emitting phosphors are considered as one of the most potential light‐conversion materials for NIR phosphor converted light‐emitting diodes (NIR pc‐LEDs). However, it is still a challenge for a single Cr3+ ion to achieve a flat ultra‐broadband emission toward multi‐functional spectroscopy applications. Herein, a chemical unit co‐substituting strategy is utilized to regulate the crystallographic occupancy of Cr3+ ions, and a flat ultra‐broadband NIR emission is successfully realized with a record emission wavelength of 915 nm in garnet‐type phosphors Ca3Sc2‐xHfxAlxSi3‐xO12: yCr3+ (0 ≤ x ≤ 1, 0.02 ≤ y ≤ 0.06), together with a large full width at half maximum (FWHM) regulation from 130 to 250 nm. The relation between the site occupation of Cr3+ ions in disordered [CaO8], [(Sc, Hf)O6] and [(Si, Al)O4] polyhedrons and the corresponding NIR emission are clarified by carefully evaluating the structural evolution, Raman spectra, electron paramagnetic resonance and time‐resolved emission lifetime spectra of Cr3+ ions. The corresponding crystal field strength of Cr3+ ions is investigated to further clarify the multi‐sites induced flat broadband NIR emission. Finally, a blue light pumped NIR pc‐LED is fabricated with a total output power of 37.58 mW and photoelectric conversion efficiency (PCE) of 13.67%@100 mA, which realizes the multi‐functional applications in night vision imaging, non‐destructive detection and palmprint vein recognition for assistant medical treatment.

中文翻译：

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通过结构调控，在 Cr3+ 掺杂石榴石型荧光粉中实现平坦的超宽带 NIR 发射，适用于多功能光谱应用


Cr3+ 活化的近红外 （NIR） 荧光粉被认为是 NIR 荧光粉转换发光二极管 （NIR PC-LED） 最具潜力的光转换材料之一。然而，对于多功能光谱应用来说，单个 Cr3+ 离子要实现平坦的超宽带发射仍然是一个挑战。在此，利用化学单元共取代策略来调节 Cr3+ 离子的晶体占有率，并在石榴石型荧光粉 Ca3Sc2‐xHfxAlxSi3‐xO12：yCr3+ （0 ≤ x ≤ 1， 0.02 ≤ y ≤ 0.06） 中成功实现了平坦的超宽带 NIR 发射，具有创纪录的 915 nm 发射波长：yCr3+ （0 x 1， 0.02 y 0.06），以及从 130 到 250 nm 的大半峰全宽 （FWHM） 调节。通过仔细评估 Cr3+ 离子的结构演变、拉曼光谱、电子顺磁共振和时间分辨发射寿命谱，阐明了无序 [CaO8]、[（Sc， Hf）O6] 和 [（Si， Al）O4] 多面体中 Cr3+ 离子的位点占据与相应的 NIR 发射之间的关系。研究了 Cr3+ 离子的相应晶体场强度，以进一步阐明多位点诱导的平坦宽带 NIR 发射。最后，制备了总输出功率为 37.58 mW、光电转换效率 （PCE） 为 13.67%@100 mA 的蓝光泵浦 NIR pc-LED，实现了辅助医疗在夜视成像、无损检测和掌纹静脉识别方面的多功能应用。