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In this article we synthesized a series of phosphors KMgGeO:Bi with high brightness for white light-emitting diodes (WLEDs) conversion and investigated their crystal structures and luminescence properties using powder X-ray diffraction, diffuse reflectance spectra, X-ray photoelectron spectroscopy, photoluminescence spectra, and absolute quantum efficiency. KMgGeO:Bi phosphor exhibits intense absorption in near-UV area and presents a broad asymmetric emission band with the main peak located at 614 nm, which was ascribed to the P → S transition of Bi. The absolute quantum efficiency of the KMgGeO:0.01Bi phosphor was measured to be 66.6%. Also, this orange emission with color chromaticity coordinates of (0.4989, 0.4400) has an excellent resistance to thermal quenching: its integrated intensity at 393 K still maintained ∼85% of the one at room temperature. The WLEDs devices with R = 93.8 were fabricated by employing KMgGeO:0.01Bi as an orange phosphor, which contains abundant red light component in its emission spectrum. The excellent luminescent performance of KMgGeO:0.01Bi suggests that it is a promising orange-emitting phosphor for near-ultraviolet WLEDs.

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