Improvement of Color Purity Using Hole Blocking Layer in Hybrid White OLED

Novel materials of Zn(HPB)2 and Ir-complexes were respectively synthesized as blue or red emitting material. White Organic Light Emitting Diodes (OLED) were fabricated by using Zn(HPB)2 for a blue emitting layer, Ir-complexes for a red emitting layer and Alq3 for a green emitting layer. White OLED was fabricated by using double emitting layers of Zn(HPB)2 and Alq3:Ir-complexes, and hole blocking layer of BCP. We also varied the thickness of BCP. When the thickness of BCP layer was 5 nm, white emission was achieved. We obtained a maximum luminance of 3,500 cd/m . The CIE coordinates was (0.375, 0.331). From this study, we could propose that the hybrid structure is efficient in lighting application of white OLED by improvement of color purity.