Wide Range Near‐Zero Thermal Quenching of Orange–Yellow Phosphor via Impeding Self‐Oxidation of Eu2+ for Versatile Optoelectronic Applications

Abstract Li 2 SrSiO 4 :Eu 2+ is a promising substitute for traditional Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) owing to its strong orange–yellow emission of 4f‐5d transition originating from Eu 2+ dopant, covering the more red‐light region. However, its inevitable luminescence thermal quenching at high temperatures and the self‐oxidation of Eu 2+ strongly impede their applications. Their remediation remains highly challenging. Herein, an anti‐self‐oxidation(ASO) concept of Eu 2+ in Li 2 SrSiO 4 substrate by adding trivalent rare‐earth ions (A 3+ : A = La, Gd, Y, Lu) for highly efficient and stable orange–yellow light emission have been proposed. A significantly increased orange–yellow emission (202% improvement) from Li 2 Sr 0.95 A 0.05 SiO 4 :Eu 2+ with a wide range near‐zero thermal quenching is obtained, superior to other Eu 2+ activated phosphors. The presence of A 3+ ions with various radii modifies the ASO degree of Eu 2+ ions, achieving the tunable chemical state, composition, electronic configuration, crystal‐field strength, and luminescent characteristics of the developed phosphors. For the proof of the concept, a W‐LED device and a PDMS (Polydimethylsiloxane) luminescent film are fabricated, endowing excellent luminescence performance and thermal stability and the huge application prospects of Li 2 SrSiO 4 :Eu 2+ in lighting and display fields.