Thermally stable K2ZnP2O7: Eu3+ red emitting phosphor for w-LEDs

Red phosphors with good luminescent properties have attracted widespread attention because they can satisfy the lighting requirement of white LEDs (Light Emitting Diode) preferably. K 2 ZnP 2 O 7 : Eu 3+ powder with a stable structure was successfully synthesized via the high-temperature solid-state method, involving a two-step process: pre-sintering at 450 °C for 12 h followed by sintering at 650 °C for 8 h. Under the excitation of 394 nm near ultraviolet light, the phosphor produces bright red emission. The highest emission peak of the K 2 Zn (1–1.5x) P 2 O 7 : xEu 3+ (x = 0.1) phosphor is located at 595 nm ( 5 D 0  →  7 F 1 ), followed by the red emission peak at 612 nm ( 5 D 0  →  7 F 2 ). When the temperature reaches 150 °C, the emission integral intensity of K 2 ZnP 2 O 7 : 0.1Eu 3+ remains 91.1% of that at room temperature (ΔE = 0.1946 eV), which proves that K 2 ZnP 2 O 7 : Eu 3+ has good thermal stability. In addition, the CIE (International Commission on Illumination) coordinates of the white LED packaged by K 2 ZnP 2 O 7 : 0.1Eu 3+ are (0.3312,0.3578), and the CCT (Correlated Color Temperature) and CRI (Color Rendering Index) of the LED lamp are 5765 K and 87.6, respectively. This indicates that K 2 ZnP 2 O 7 :Eu 3+ is promised as a red-emitting phosphor for white LED excited by near-ultraviolet chips.