Ultra-thin polymer-encapsulation of SrAl2O4 :Eu2+, Dy3+ phosphor for enhancedhydrolytic resistance

• Published in: The Korean journal of chemical engineering pp. 2548 - 2554
• Main Authors: 이향무, 허준희, 김진철, 주진, 정인우
• Format: Journal Article
• Language: English
• Published: 한국화학공학회 01.09.2022
• Subjects: 화학공학
• ISSN: 0256-1115; 1975-7220
• DOI: 10.1007/s11814-022-1103-6

Eu2+ and Dy3+ doped strontium aluminates (SrAl2O4 : Eu2+, Dy3+) are well known green light emitting materialswith a long-lasting afterglow property; however, SrAl2O4 : Eu2+,Dy3+ is readily hydrolized under ambient moistureconditions, which impedes industrial applications. In this work, SrAl2O4 : Eu2+, Dy3+ phosphor was encapsulated bylayer-by-layer (LbL) and coacervation methods for the formation of ultra-thin polymeric capsulation layer. Morphologyof the phosphor and polymer-encapsulated phosphors was characterized by scanning electron microscopy (SEM).The amount and thickness of the encapsulated polymer layers were analyzed by thermogravimetric analysis (TGA) andatomic force microscopy (AFM), and the polymer content for the phosphor encapsulated by LbL was estimated to be0.08 wt% with a shell thickness of 11 nm. After pristine phosphor and encapsulated phosphor samples were immersedin water for 24 h, the photoluminescence (PL) intensity was measured to compare the water-resistant performance. Thepolymer-encapsulated phosphors by LbL and coacervation methods were maintained for 85.7 and 93.5% of pristinephosphors, respectively, while PL intensity of the pristine phosphor was observed as 18.1% after immersion in water for24 h. The change in pH was monitored under the same conditions. The pH for the dispersion of polymer-encapsulatedphosphors by LbL and coacervation methods was measured as 10.27 and 9.63, respectively, while pH for the dispersionof the pristine phosphor was observed as 11.99. This research may provide a wider option for the encapsulationmethods of particulate materials for applications where encapsulation with very thin layer of polymer is needed,because the encapsulation process inevitably lowers both the content of active ingredients and consequently their performanceas well. KCI Citation Count: 0