고출력 백색 LED/LD을 위한 발광체 개발
|
임원빈 한양대학교 Phosphor-converted white light-emitting diodes (pc-WLEDs) and laser diodes (pc-LDs) are the efficient light source that has multifarious applications in lighting, high-tech displays, electronic devices, and headlight application. One of the biggest challenge of them is the thermal quenching (TQ), in which phosphor suffers from emission loss with increasing temperature during high-power LED/LD operation and is an inevitable drawback for any existing phosphor. Here, we present robust and none-TQ WLEDs/LDs using various strategies to overcome the TQ and efficiency decrease by means of (1) phosphor-plate with high thermal conductivity by graphene-wrapping, (2) by rotation-wheel using phosphor-plate, and (3) a zero-thermal-quenching phosphor. In particular, for the first time, a new blue-emitting phosphor that doesn’t exhibit TQ revealing zero-emission loss even up to 250ºC. This phenomena of a zero-thermal quenching, denoted as self-healing phosphor, portrays the ability of phosphor in resurrecting the emission loss and sustaining the luminescence with increasing temperature. This finding would initiate the exploration of many self-healing phosphors with zero-thermal quenching for high-power LED/LD applications. |