Superb thermal stability purple-blue phosphor through synergistic effect of emission compensation and nonradiative transition restriction of Eu2+. (June 2022)

• Record Type: Journal Article
• Authors: Sun, Z.; Sun, B.; Zhang, X.; Wen, D.; Dai, P.
• Is Part Of: Materials today chemistry. Volume 24(2022)
• Publication Date: 2022-06
• Subjects: Phosphors -- High thermal stability -- Large bandgap -- High structural rigidity -- Self-compensated emission; Chemistry -- Periodicals; Materials -- Research -- Periodicals; Materials science -- Periodicals; Chemistry; Materials -- Research; Electronic journals; Periodicals; 660.282
• DOI: 10.1016/j.mtchem.2022.100877
• Languages: English
• ISSNs: 2468-5194

Abstract

Abstract: Phosphors with outstanding luminescence thermal stability are desirable for high-power phosphor-converted light-emitting diode (pc-LED) lightings. High structural rigidity and large bandgap of phosphor hosts are helpful to suppress nonradiative relaxation of optical centers and realize excellent thermal stability. Unfortunately, few host materials simultaneously possess aforementioned structural features. Herein, we confirm that Sr3 (PO4 )2 (SPO) phosphate possesses high structural rigidity (Debye temperature, ΘD = 559 K) and large bandgap (Eg = 8.313 eV) by density functional theory calculations. As expected, Eu 2+ -doped SPO purple-blue phosphors show extraordinary thermal stability. At 150/300 °C, SPO:5%Eu 2+ presents emission loss of only 4%/8% and a predicated ultrahigh thermal quenching temperature of 973 °C. The most strikingly discoveries here are that thermal-induced emission compensation appears within two distinct Eu 2+ sites of SPO host. The outstanding thermal stability, on one hand, is attributed to rigid structure and large bandgap of host that inhibits nonradiative relaxation of Eu 2+ and on the other hand, the emission self-compensation of Eu 2+ . Benefiting from synergistic effect of emission compensation and nonradiative transition restriction of Eu 2+, as-prepared SPO:5%Eu 2+ purple-blue phosphor not only presents superior thermal stability but also high internal quantum efficiency of 95.1% and excellent hydrolysis resistant. Some advanced applications are explored including white LED lighting and wide-color-gamut display. Our work provides in-deep insights into structure-property relationships of thermally stable phosphors. Graphical abstract: Image 1 Highlights: High structural rigidity (ΘD =559K) and large bandgap (Eg =8.313eV) are demonstrated in Sr3 (PO4 )2 host. At 150/300 °C, SPO:5%Eu 2+ presents emission loss of only 4%/8% and a predicated ultrahigh TQ temperature of 973 °C. High thermal stability benefits from synergistic effect of emission compensation and nonradiative restriction of Eu 2+ .