Novel orange-red emitting Sr3Ga2Ge4O14: Sm3+ phosphors with high color purity for red-backlight display and white LEDs

Novel langasite family (Sr3Ga2Ge4O14: Sm3+) phosphors with orange-red emitting were successfully synthesized via a conventional high-temperature solid-phase method. The X-ray diffraction, field emission scanning electron microscopy and FT-IR spectroscopy were employed to characterize the prepared samples in detail. Upon the excitation of 401 nm, the strongest emission peak was found at 598 nm. The optimal doping concentration and highest PL performance for Sm3+-doped sample was 7 % mol with excellent color purity of 99.41 %, and the concentration quenching mechanism was verified to be dipole-quadrupole interaction. Simultaneously, the temperature-dependent PL emission spectra indicated that the investigated phosphors exhibited good thermal stability performance. The prepared red-LEDs and w-LEDs using SGG: 7%Sm3+ phosphors can emit bright red and white lights, respectively. Meanwhile, the packaged w-LEDs exhibited low correlated color temperature (CCT = 5434 K) and high color rendering index (CRI = 81). The results reveal that the prepared SGG: Sm3+ phosphors exhibited potential applications in both red background display and indoor lighting.