A novel high efficiency and ultra-stable red emitting europium doped pyrophosphate phosphor for multifunctional applications

The development of high quantum efficiency and stable red emitting phosphors with high color purity is an urgent need for multifunctional optical applications. In this work, we propose a nonlinear optical material (NLOM)-inspired methodology to synthesize a novel red emission pyrophosphate phosphor Rb2Ba3(P2O7)2:Eu3+. XRD Rietveld refinement and energy dispersive X-ray spectroscopy were then exploited to obtain information on the phase purity, crystal structure and chemical composition. Moreover, the optical bandgap of different Eu3+ doped Rb2Ba3(P2O7)2 phosphors was analyzed by diffuse reflectance spectroscopy and further confirmed by first principles calculation. Furthermore, the Eu3+ site occupation preference, the characteristic luminescence properties and luminescence kinetics as a function of Eu3+ doping concentration were investigated by employing the cryogenic spectra at 4 K, room temperature emission spectra and decay curves. The luminescence analysis indicated that Rb2Ba3(P2O7)2:Eu3+ could emit red emission light with high quantum efficiency (IQE ∼ 77.04%), high color purity (96.4%) and excellent thermal stability (87%@ 140 °C) under ultraviolet light excitation. In addition, the excellent stability of Rb2Ba3(P2O7)2:Eu3+ against external pressure, cathode-ray irradiation, water and acid–base was further proved by pressure-driven (from 0 to 20 GPa) luminescence analysis, cathodoluminescence analysis and emission photography after infiltrating in water, acid, and alkali. The current work indicates that Rb2Ba3(P2O7)2:Eu3+ exhibits unprecedented excellent luminescence properties compared to other recently discovered phosphate red phosphors, and can serve as a potential red phosphor candidate in multifunctional optical applications, like LEDs, FEDs, artistic appreciation or some applications under extreme conditions (high temperature, strong pressure, and infiltrating in water, acid, and alkali).