Bright emission and high photoluminescence CsPb2Br5 NCs encapsulated in mesoporous silica with ultrahigh stability and optical properties for excellent white light emitting diodes
All inorganic cesium lead halide perovskite CsPb2Br5 nanocrystals (NCs) have attracted tremendous attentions owing to their unique optoelectronic properties, however, exposure to atmospheric moisture is limited by its corresponding poor stability, which has drastically prevented broad applications of the materials in lasers, light emitting diodes (LED) and the most recently photocatalysis. To address this issue, we have successfully demonstrated the design and synthesis of the high photoluminescence (PL) intensity and bright emission CsPb2Br5 NCs coated in mesoporous silica (NCs-MS) nanocomposites material with effectively enhanced the water resistance stability, thermal stability and photostability for at least 50 days than that of naked CsPb2Br5 NCs. The component and structure of the as prepared CsPb2Br5 NCs-MS nanocomposites were investigated in detail by PL, XRD, TEM and HAADF-STEM, etc. And the mechanism of the outstanding stability and optical properties has been discussed for the as prepared NCs-MS nanocomposites. Due to the ultrahigh stability of the NCs-MS nanocomposites, it has been found that the white LED (WLED) assembled by coating CsPb2Br5 NCs-MS nanocomposites and commercial red CaAlSiN3:Eu2+ phosphor powders on a InGaN blue chip shown a CIE chromaticity coordinate (0.3377, 0.3309) and presented excellent optical parameters that a CRI of 82.9, CCT of 5035 K and LE of 64.9 lm/W. This work would provide a new pathway for the synthesis and applications of all inorganic cesium lead halide perovskite materials in the fields of WLED and display devices.