Original Article:
A rapid in situ synthesis of wide-spectrum CD@BaCl2 phosphors via anti-solvent recrystallization for white LEDs
Jinhui Liang, et al.
Inorganic Chemistry Frontiers, 2020, 7(24): 4845-4853.
10.1039/D0QI01054E
In order to develop solid-state carbon dots with good photoluminescence properties at both room temperature and high temperature, a facile and rapid anti-solvent-induced in situ recrystallization is applied here. The carbon dots act as seeds for heterogeneous nucleation, encapsulating them into the barium chloride (BaCl2) crystals. The as-prepared CD@BaCl2 exhibits excellent photoluminescence thermal stability (90% of initial intensity at 423 K). In addition, the color rendering index of white LEDs optimized by CD@BaCl2 can be greatly improved from 78.6 to 89.1.
The schematic diagram of the synthesis of CD@BaCl2 composite is shown in the figure. Advantages of barium chloride as a dispersion medium in this study:
1. The big solubility difference of BaCl2 in water and ethanol favors an in situ anti-solvent-induced recrystallization, where the CDs act as seeds of heterogeneous nucleation and can be well-dispersed in the recrystallized BaCl2 crystals, thereby inhibiting the in intrinsic electron– electron energy.
2. BaCl2 has a wide bandgap of 8.0 eV, which is large enough to prevent the electron-electron coupling between the CDs and media. Additionally, BaCl2 has a low phonon energy of only 200 cm-1, even lower than the widely recognized low-phonon-energy matrix NaYF4 (350 cm-1), showing a great potential to reduce the electron-phonon coupling between the CDs and media.
Chemicals Related in the Paper:
| Catalog Number | Product Name | Structure | CAS Number | Price |
|---|---|---|---|---|
| ACM10326279 | Barium Chloride Dihydrate |  |
10326-27-9 | Price |
