Luminescent materials widely used for optical devices, such as light-emitting-diode, plasma display and liquid crystal display rely on the inner-shell transition of rare earth (RE) elements. Unstable RE supply, however, accelerates the importance for developing RE-free luminescent materials. Silicon-oxycarbide (SiOC) has been a promising candidate for white luminescent materials [1], and recently, the present research group found that the mesoporous carbon silica (MPCS) nanocomposite with large surface area emits strong white PL, depending on the degrees of hydrolysis and polycondensation reactions in preparing MPCS [2]. The MPCS nanocomposite consists of a periodic honeycomb silica framework with pores of ~8 nm in diameter.
The synthesis procedures of the MPCS nanocomposite was described in detail elsewhere [3]. The sample was ground by an agate mortar and pestle into fine powder, which was sprinkled on a carbon coated micro-grid. The sample thus prepared was examined using a JEOL JEM-ARM200F STEM (double Cs-corrected) operated at 80 kV and a Gatan Image Filter Quantum ER and an FEI Titan equipped with a Gatan Vulcan TEM-CL system, operated at 80 kV at LN2 temperature for elemental/emission mapping.