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There is a significant need to identify cyan-emitting phosphors capable of filling the “cyan-gap” (480–520 nm) in full-visible-spectrum phosphor-converted white light-emitting diodes (pc-wLEDs). Here, a new broadband cyan-emitting phosphor that enables addressing of this challenge is reported. The compound, Ba 2 CaB 2 Si 4 O 14 :Ce 3+ , presents a bright cyan emission peaking at 478 nm with a large full width at half maximum of 142 nm (6053 cm −1 ), and minimal thermal quenching. The photoluminescence properties originate from Ce 3+ residing at two different crystallographic sites, a [BaO 9 ] distorted elongated square pyramid and a [CaO 6 ] trigonal prism. This combination results in an efficient, broad emission covering the blue to green region of the visible spectrum. Fabricating a simple dichromatic ultraviolet ( λ ex = 370 nm) pumped pc-wLED using Ba 2 CaB 2 Si 4 O 14 :Ce 3+ along with a commercially available red phosphor demonstrates full-visible-spectrum white light with high color rendering index ( R a > 90) and tunable correlated color temperature, showing the potential of this material for achieving high-quality LED-based lighting. 

Efficient broadband near‐infrared (NIR) emitting materials with an emission peak centered above 830 nm are crucial for smart NIR spectroscopy‐based technologies. However, the development of these materials remains a significant challenge. Herein, a series of design rules rooted in computational methods and empirical crystal‐chemical analysis is applied to identify a new Cr³⁺‐substituted phosphor. The compound GaTaO₄:Cr³⁺emerged from this study is based on the material's high structural rigidity, suitable electronic environment, and relatively weak electron–phonon coupling. Irradiating this new phosphor with 460 nm blue light generates a broadband NIR emission (λ_em,max = 840 nm) covering the 700–1100 nm region of the electromagnetic spectrum with a full width at half maximum of 140 nm. The phase has a high internal quantum yield of 91% and excellent thermal stability, maintaining 85% of the room temperature emission intensity at 100 °C. Fabricating a phosphor‐converted light‐emitting diode device shows that the new compound generates an intense NIR emission (178 mW at 500 mA) with photoelectric efficiency of 6%. This work not only provides a new material that has the potential for next‐generation high‐power NIR applications but also highlights a set of design rules capable of developing highly efficient long‐wavelength broadband NIR materials.