Full Extraction of 2D Photonic Crystal Assisted $\hbox {Y}_{3}\hbox {Al}_{5}\hbox {O}_{12}$ :Ce Ceramic Plate Phosphor for Highly Efficient White LEDs

In this paper, we report the optical and thermal effects of filling the air gap between a ceramic plate phosphor (CPP) and a cup-type light-emitting diode (LED) in a white phosphor-converted LED (pc-LED) package. The aim of our work was to improve extraction efficiency fully, as well as to enhance heat dissipation; and in this case, the CPP was a two-dimensional (2D) TiO₂ nanobowl photonic crystal layer (PCL)-assisted Y₃Al₅O₁₂: Ce^{3 +}(YAG: Ce). By adding a 2D TiO₂ PCL and eliminating the air gap between the CPP and the LED cup, our package exhibited better luminous efficacy, more uniform optical properties, and higher thermal conductivity than those of a 2D TiO₂ PCL-assisted CPP-capped LED with an air gap and a conventional phosphor powder dispersed in an LED package.