| Abstract Scope |
Single-crystal phosphors (SCPs), which exhibit a superior conversion efficiency, a high thermal stability and a low temperature increase under high-power irradiation, are proposed for high brightness (HB) white lighting applications. SCPs possess a high purity and crystalline quality, thus guarantying best performance in either bulk or powder form. The best yellow phosphor for white LEDs is Ce:YAG, and its emission can be tuned towards the green by Lu substitution. SCPs exhibit an outstanding internal quantum efficiency (QE); at room temperature it’s over 95%, and with the temperature rise it increases even further, reaching a maximum at about 250oC. Instead, the internal QE of CPPs even quenches at much lower temperatures, indicating the presence of undesired non-radiative recombination paths. These show that, SCPs meet the fundamental requirements for emerging HB applications such as laser headlights and laser projectors. Binder-free SCP powder plate is demonstrated, and it has shown the same performance. |