형광체의 색변환층을 이용한 백색 유기발광소자의 연색지수 강화 메커니즘

Abstract

White organic light-emitting devices (WOLEDs) have attracted great attention because of their potential applications in full-color displays, backlights for liquid crystal displays, and solid-state lighting sources. The prospect of potential applications of OLEDs in lighting sources has led to substantial research and development efforts. The white lighting sources fabricated by using blue and red organic light-emitting devices (OLEDs) with a color-conversion phosphor layer have been extensively performed to achieve their good color stability. Even though some studies concerning the fabrication and the device characteristics of WOLEDs consisting of blue OLED with a color-conversion phosphor layer have been conducted, their color rendering indices (CRI) are not high enough for the utilization lighting sources. Therefore, systematic studies on the enhancement of the CRI for the of WOLEDs with a color conversion layer(CCL) utilizing phosphors play an important role for practical applications in lighting sources This paper reports data for WOLEDs fabricated utilizing a CCL made of Y3Al5O12:Ce3+ green phosphors. The Y3Al5O12:Ce3+ phosphors were synthesized by a sol-gel method. X-ray diffraction data for the synthesized Y3Al5O12:Ce3+phosphor films showed that the Y3Al5O12:Ce3+phosphor films were crystallized. Electroluminescence (EL) spectra for WOLEDs fabricated utilizing a CCL showed that the Commission Internationale de l’Eclairage (CIE) chromaticity coordinates corresponded to the white emission. The blue and red light from the double emission OLEDs in WOLEDs combined with a green light emitted from the Y3Al5O12:Ce3+phosphor layer resulted in a white emission. EL spectra demonstrated that the CRI value was improved by using Y3Al5O12:Ce3+ phosphor CCL.