Hyun-Joo Woo

A highly efficient warm white light-emitting Eu2+-activated silicate host: another striking application of mesoporous silica

This study outlines a novel approach to the synthesis of an efficient yellow-emitting Sr0.975Ca0.975Eu0.05SiO4 phosphor with the adequate red spectral components. This was achieved by the use of a well-known silicate source, mesoporous silica. The findings showed that the synthesized phosphor gave a broad emission from blue to red, along with a stable emission color till 450 K and an emission decay time of 1 μs. When the phosphor was fabricated using UV (400 nm) and blue LED (450 nm) chips, it promisingly generated warm white light at a color temperature 80.

Mesoporous silica: a highly promising and compatible candidate for optical and biomedical applications

A simple post-co-precipitation strategy is adopted for the construction of a mesoporous silica framework in which the rare earth gadolinium oxide (Gd2O3:Eu3+& Gd2O3:Sm3+, Eu3+) is incorporated as an emissive probe for optical and bio-medical applications. The samples show good emission along with the required theranostic properties. In the blue region, a better red emissive behavior is observed in the case of Eu3+ doped sample while the Sm3+ and Eu3+ co-doped sample exhibit the same in the near ultra-violet region. Moreover, the structural and textural properties of mesoporous silica are preserved even in the presence of rare earth doped Gd2O3 and this can very well be utilized for theranostic applications. A clear confocal microscopy image shows a red spot, and thus its potential towards trackability is confirmed. In addition to this, other admirable properties are also associated with it namely, an excellent drug loading ability, bio-compatibility, easy surface modification by the targeting moiety and excellent longitudinal relaxivity (T1) under magnetic resonance imaging (MRI), which stands par for it to be utilized in the field of theranostics too. This material shows good luminescence properties along with the desired internal–external morphology, and a narrowly ordered porosity can validate the application of these materials in multi-faceted fields such as phosphors for LEDs, bio-imaging, theranostics etc.

A novel efficient mesoporous silica assisted green emitting phosphors-an exotic remote phosphor with high quantum yield

A novel attempt towards the development of Eu2+ doped barium silicate and strontium barium silicate has been put forth using a versatile material, namely mesoporous silica through a convenient wet-solid phase reaction. The developed phosphor can be efficiently excited in a broad spectral range of 200–500 nm, and gets emitted strongly in the green region. On introduction of strontium to Eu2+ doped barium silicate phosphor, a clear red shift has been recorded in the photoluminescence spectra. These mesoporous silica assisted synthesis of Ba1.95Eu0.05SiO4 and Ba0.975Sr0.975Eu0.05SiO4 phosphors showed a good thermal luminescence stability and high quantum efficiency of about 85%. It has been successfully used for the fabrication of a flexible and translucent remote phosphor. The fabricated remote phosphor attached proto-type LED exhibits a very strong green emission and this can be utilized as an efficient green component for various applications apart from the white LED productions.