Layered Crystal Structure, Color-Tunable Photoluminescence, and Excellent Thermal Stability of MgIn₂P₄O₁₄ Phosphate-Based Phosphors

Abstract

Single-component white phosphors stand a good chance to serve in the next-generation high-power white light-emitting diodes. Because of low thermal stability and containing lanthanide ions with reduced valence state, most of reported phosphors usually suffer unstable color of lighting for practical packaging and comparably complex synthetic processes. In this work, we present a type of novel color-tunable blue-white-yellow-emitting MgInPO:Tm/Dy phosphor with high thermal stability, which can be easily fabricated in air. Under UV excitation, the MgInPO:TmDy white phosphor exhibits negligible thermal-quenching behavior, with a 99.5% intensity retention at 150 °C, relative to its initial value at room temperature. The phosphor host MgInPO was synthesized and reported for the first time. MgInPO crystallizes in the space group of C2/c (No. 15) with a novel layered structure built of alternate anionic and cationic layers. Its disordering structure, with Mg and In atoms co-occupying the same site, is believed to facilitate the energy transfer between rare-earth ions and benefit by sustaining the luminescence with increasing temperature. The measured absolute quantum yields of MgInPO:Dy, MgInPO:TmDy, and MgInPO:TmDy phosphors under the excitation of 351 nm ultraviolet radiation are 70.50%, 53.24%, and 52.31%, respectively. Present work indicates that the novel layered MgInPO is a promising candidate as a single-component white phosphor host with an excellent thermal stability for near-UV-excited white-light-emitting diodes (wLEDs).

Effects of the deep traps on the thermal‐stability property of CaAl2O4: Eu2+ phosphor

“…White light emitting diodes (wLEDs) have been widely used in daily life due to their eco‐friendly properties, easy fabrication, high efficiency, low cost, and long luminescent lifetime . The traditional wLEDs are prepared by combining a blue LED chip with yellow‐emitting Y 3 Al 5 O 12 : Ce 3+ (YAG: Ce 3+ ) phosphors . Another approach for producing wLEDs is via combining red‐, green‐, and blue‐emitting phosphors with a near ultraviolet (NUV) LED chip .…”

Luminescence properties of novel Eu3+‐doped tantalate NaCaTiTaO6 red‐emitting phosphors for solid‐state lighting

“…Thermal quenching can be well‐explained using a configurational coordinate diagram where the excited luminescent center is thermally activated through phonon interaction, and then relaxed to the groud state through crossover process …”

“…Thermal quenching can be well-explained using a configurational coordinate diagram where the excited luminescent center is thermally activated through phonon interaction, and then relaxed to the groud state through crossover process. 23,35,36 In the above process, the electron needs to absorb some energy to overcome a certain energy barrier (ΔE); therefore, the greater the ΔE is, the more difficult the crossover process to occur. 23 To better comprehend the relationship between emission intensity and temperature of NaCaTiTaO 6 :xEu 3+ (x = 0.02-0.50) and confirm the activation energy of thermal quenching, the experimental data of NaCaTiTaO 6 :xEu 3+ was fit by the Arrhenius equation: 37,38 where I 0 and I(T) represent the emission intensity of the phosphor at temperature 300 K and T, c is a constant for any host, E a is the activation energy, k is the Boltzmann's constant (8.62 × 10 −5 eV/K).…”

Oxygen vacancy content drives self-reduction and anti-thermal quenching

“…1,2 In general, there are two ways to obtain the products, either coating yellow-emitting YAG:Ce 3+ on a blue InGaN chip or combining tricolor phosphors with a near ultraviolet (n-UV) chip. 3,4 As one of the indispensable raw materials, phosphors are critical to the performances of as-fabricated lighting lamps, like color rendering index (R a ) and correlated color temperature (CCT). 5 Among several parameters of the primary components, thermal stability plays a decisive role in their practical applications.…”