Recent Advances in Red Phosphors Used in White LED

Because of its long life, low energy consumption, small volume and harmlessness to the environment, white light-emitting diode(LED) has aroused extensive attention. But higher color temperature, lower color rendering index and higher cost limit the extensive application of white LED. Red phosphors play a critical role in raising the color rendering index and reducing the color temperature, so it becomes a hotspot. The recent adcances in red phosphors used in whith LED are reviewed, and red line emission phosphors activated by Eu3+, Sm3+, red broad band emission phosphors activated by Eu2+,Ce3+, red phosphors activated by Mn4+, Mn2+and the synthetic menthods of red phosphors are mainly introduced. The problems such as higher cost, smaller variety and the synthesis of red phosphors in large quantities restricted to solid-state reaction are pointed. Solving these problems is the main research direction in future.