Schwab Thomas, Aicher Korbinian, Razouq Hasan, Zickler Gregor A, Diwald Oliver
Department of Chemistry and Physics of Materials, Paris-Lodron University of Salzburg, Jakob-Haringer-Straße 2a, Salzburg 5020, Austria.
ACS Appl Mater Interfaces. 2021 Jun 2;13(21):25493-25502. doi: 10.1021/acsami.1c02931. Epub 2021 May 19.
Nanostructured segregates of alkaline earth oxides exhibit bright photoluminescence emission and great potential as components of earth-abundant inorganic phosphors. We evaluated segregation engineering of Ca- and Ba-admixtures in sintered MgO nanocube-derived compacts. Compaction and sintering transform the nanoparticle agglomerates into ceramics with residual porosities of = 24-28%. Size mismatch drives admixture segregation into the intergranular region, where they form thin metal oxide films and inclusions decorating grain boundaries and pores. An important trend in the median grain size evolution of the sintered bodies with = 90 nm < = 160 nm < = ∼ = 280 nm < = 870 nm is rationalized by segregation and interface energies, barriers for ion diffusion, admixture concentration, and the increasing surface basicity of the grains during processing. We outline the potential of admixtures on interface engineering in MgO nanocrystal-derived ceramics and demonstrate that in the sintered compacts, the photoluminescence emission originating from the grain surfaces is retained. Interior parts of the ceramic, which are accessible to molecules from the gas phase, contribute with oxygen partial pressure-dependent intensities to light emission.
碱土金属氧化物的纳米结构偏析物表现出明亮的光致发光发射，并且作为储量丰富的无机磷光体的组分具有巨大潜力。我们评估了烧结的MgO纳米立方体衍生压块中Ca和Ba混合物的偏析工程。压实和烧结将纳米颗粒团聚体转变为具有24 - 28%残余孔隙率的陶瓷。尺寸失配促使混合物偏析到晶间区域，在那里它们形成装饰晶界和孔隙的薄金属氧化物膜和夹杂物。烧结体中位晶粒尺寸演变的一个重要趋势（90 nm < 160 nm < ∼ = 280 nm < 870 nm）可通过偏析和界面能、离子扩散势垒、混合物浓度以及加工过程中晶粒表面碱性的增加来解释。我们概述了混合物在MgO纳米晶衍生陶瓷界面工程中的潜力，并证明在烧结压块中，源自晶粒表面的光致发光发射得以保留。陶瓷内部部分可被气相分子接触，其对发光的贡献强度与氧分压有关。
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