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Full-spectrum lighting has become the development direction for human-centric illumination. However, the reabsorption effect caused by cyan, green and yellow multiple-phosphor packaging leads to low luminous efficiency. In this work, a broadband cyan-green phosphor is proposed to replace the cyan and yellow phosphors for highly efficient and thermally robust full-spectrum WLEDs. A new family of oxyfluoride garnet phosphors Lu 2 QMg 2 Al 3 O 9 F 3 : Ce3+ (Q = Ca, Sr, Ba) has been developed by incorporating F- into the classic LuAG: Ce3+ green phosphor. The excess charge was compensated by substituting trivalent Lu3+ and Al3+ with divalent alkaline earth element. The low covalency and phonon energy of fluorine-containing system endow these serial phosphors with efficient and thermally stable blue-shifted emission. The representative Lu 2 SrMg 2 Al 3 O 9 F 3 : Ce3+ exhibits a broadband cyan-green emission peaked at 513 nm with a 105 nm FWHM. Furthermore, outstanding quantum efficiency (88.4%) and thermal stability (94.3% @ 423 K) were achieved. This oxyfluoride phosphor was packaged with red phosphor without cyan phosphor on a blue chip. The obtained WLEDs show an excellent color rendering index (R a = 96.8) with luminous efficiency (LE = 106 lm/W). This research might pave a promising avenue for the development of next-generation full-spectrum lighting. • A new family of oxyfluoride garnet cyan-green phosphors was obtained. • The F- incorporation endows the phosphors with efficient and thermally stable blue-shifted emission. • The Lu 2 SrMg 2 Al 3 O 9 F 3 : Ce3+ exhibits a 513 nm centered emission with a 105 nm FWHM. • Ra=96.8 and LE=106 lm/W were achieved by replacing the cyan and yellow phosphor. [ABSTRACT FROM AUTHOR]