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http://dx.doi.org/10.4218/etrij.14.0113.0845

Surface Control of Planarization Layer on Embossed Glass for Light Extraction in OLEDs  

Cho, Doo-Hee (Components & Materials Research Laboratory, ETRI)
Shin, Jin-Wook (Components & Materials Research Laboratory, ETRI)
Moon, Jaehyun (Components & Materials Research Laboratory, ETRI)
Park, Seung Koo (Components & Materials Research Laboratory, ETRI)
Joo, Chul Woong (Components & Materials Research Laboratory, ETRI)
Cho, Nam Sung (Components & Materials Research Laboratory, ETRI)
Huh, Jin Woo (Components & Materials Research Laboratory, ETRI)
Han, Jun-Han (Components & Materials Research Laboratory, ETRI)
Lee, Jonghee (Components & Materials Research Laboratory, ETRI)
Chu, Hye Yong (Components & Materials Research Laboratory, ETRI)
Lee, Jeong-Ik (Components & Materials Research Laboratory, ETRI)
Publication Information
ETRI Journal / v.36, no.5, 2014 , pp. 847-855 More about this Journal
Abstract
We developed a highly refractive index planarization layer showing a very smooth surface for organic light-emitting diode (OLED) light extraction, and we successfully prepared a highly efficient white OLED device with an embossed nano-structure and highly refractive index planarization layers. White OLEDs act as an internal out-coupling layer. We used a spin-coating method and two types of $TiO_2$ solutions for a planarization of the embossed nano-structure on a glass substrate. The first $TiO_2$ solution was $TiO_2$ sol, which consists of $TiO_2$ colloidal particles in an acidic aqueous solution and several organic additives. The second solution was an organic and inorganic hybrid solution of $TiO_2$. The surface roughness ($R_a$) and refractive index of the $TiO_2$ planarization films on a flat glass were 0.4 nm and 2.0 at 550 nm, respectively. The J-V characteristics of the OLED including the embossed nano-structure and the $TiO_2$ planarization film were almost the same as those of an OLED with a flat glass, and the luminous efficacy of the aforementioned OLED was enhanced by 34% compared to that of an OLED with a flat glass.
Keywords
Light extraction; OLED; out-coupling; refractive index; planarization;
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Times Cited By KSCI : 2  (Citation Analysis)
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