Mn-activated　oxides　have　been　widely　regarded　as　a　new　class　of　red　phosphors,　while　the　weak　absorption　of　blue　light,　low　quantum　yield　(QY),　and　insufficient　thermal　quenching　performance　limit　their　applications.　In　this　study,　a　series　of　deep-red　emitting　Ca14Al9.8Zn6−xMg0.1+xMn0.1O35　phosphors　with　outstanding　luminescence　performances　are　fabricated,　and　their　optical　and　vibrational　properties,　as　well　as　the　thermal　quenching　mechanism,　are　investigated.　The　partial　substitution　of　Mg　for　Zn　not　only　greatly　improves　the　absorption　capability　of　blue　light,　but　also　suppresses　the　crystal　defects,　resulting　in　high　QY　(85.9%　with　excitation　at　460　nm)　and　low　thermal　quenching　effect　(the　emission　intensity　remains　~99.2%　at　460　K　and　~60.8%　at　580　K　relative　to　that　at　300　K).　This　work　demonstrates　the　great　potential　applications　of　Ca14Al9.8Zn6−xMg0.1+xMn0.1O35　phosphors　in　LED　devices.　©　2021　Elsevier　B.V.