• Korean Journal of Materials Research
• /
• v.17 no.4
• /
• pp.198-202
• /
• 2007

A new organic light emitting device(OLED) with two peak wavelength(blue and yellow) emission was fabricated using the selective doping in a single fluorescent host , and its electrical and optical characteristics were investigated. The fabricated device showed the luminance and efficiency of 1600 $Cd/m^2$ and 2.4 Im/W under the applied voltage of 10V, respectively. And its electroluminescent spectra had two peak wavelengths of 470nm and 560nm emitting bluish white light. The OLED with dual wavelength emission in this experiment is likely to be developed as a white OLED with simpler fluorescent system than conventional devices.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.1
• /
• pp.15-21
• /
• 2012

In this study, the characteristics of the 2-wavelength white organic light-emitting diod (WOLED) with two colors of yellow and blue were compared and analyzed with 3-wavelength WOLED with three colors of red, green, and blue. The results indicated that the power efficiency of the 2-wavelength WOLED was 1.6 times higher than 3-wavelength WOLED. In addition, the colot coordinate of the 2-wavelenth WOLED which was (0.34, 0.39) was found closer to the optimal color coordinate for the white-lighting application when compared with that of the 3-wavelength WOLED.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.9
• /
• pp.581-586
• /
• 2015

We studied optical and electrical properties of two-wavelength white tandem organic light-emitting diodes using red and blue materials. White fluorescent OLEDs were fabricated using Alq3 : Rubrene (3 vol.% 5 nm) / SH-1 : BD-2 (3 vol.% 25 nm) as emitting layer (EML). White single fluorescent OLED showed maximum current efficiency of 9.7 cd/A, and tandem fluorescent OLED showed 18.2 cd/A. Commission Internationale de l'Eclairage (CIE) coordinates of single and tandem fluorescent OLEDs was (0.385, 0.435), (0.442, 0.473) at $1,000cd/m^2$, respectively. White hybrid OLEDs were fabricated using SH-1 : BD-2 (3 vol.% 10 nm) / CBP : $Ir(mphmq)_2(acac)$ (2 vol.% 20 nm) as EML. White single hybrid OLED showed maximum current efficiency of 7.8 cd/A, and tandem hybrid OLED showed 26.4 cd/A. Maximum current efficiency of tandem hybrid OLED was more twice as high as single OLED. CIE coordinates of single hybrid OLED was (0.315, 0.333), and tandem hybrid OLED was (0.448, 0.363) at $1,000cd/m^2$. CIE coordinates in white tandem OLEDs compared to those for single OLEDs observed red shift. This work reveals that stacked white OLED showed current efficiency improvement and red shifted emission than single OLED.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.2
• /
• pp.217-222
• /
• 2004

The white-light-emitting organic LED(OLED) with two-wavelength was fabricated using the DPVBi of blue emitting material and a series of orange color fluorescent dye(Rubrene) by vacuum evaporation processes. The basic structure of white-light-emitting OLED was ITO/NPB(150$\AA$)/DPVBi/Rubrene/BCP(100$\AA$)/Alq$_3$(150$\AA$)/Al(600$\AA$). We analyzed the fabricated device through the changes of the DPVBi and Rubrene layer's thickness. We obtained the white-light-emitting OLED with white color light and the CIE coordinate of the device was (0.29, 0.33) at applied voltage of 13V when the thickness of DPVBi layer was 210$\AA$ and the thickness of Rubrene layer was 180$\AA$. At a current of 100㎃/$\textrm{cm}^2$, the quantum efficiency was 0.35％ and at a voltage of 20V, it was 0.405％.

• 전자공학회논문지 IE
• /
• v.43 no.2
• /
• pp.1-6
• /
• 2006

The white organic light emitting diode(OLED) with two-wavelength was fabricated using the DPVBi of blue emitting material and a series of orange colar fluorescent dye(Rubrene) by vaccum evaporation processes. The basic structure of OLED was ITO/TPD$(225{\AA})$/DPVBi/Rubrene/BCP$(210{\AA})/Alq_3(225{\AA})/Al(1000{\AA})$. We analyzed the fabricated device through the changes of the DPVBi and Rubrene layer's thickness. We obtained the white OLED with the CIE coordinate of the device was (0.29, 0.33) and luminescence of $1000cd/m^2$ at applied voltage of 15V when 4he thickness of DPVBi layer was 210${\AA}$ and the thickness of Rubrene layer was 180${\AA}$.

• Journal of the Microelectronics and Packaging Society
• /
• v.13 no.4
• /
• pp.71-75
• /
• 2006

The yellow emitting OLED using GDI602:Rubrene(10%) material has been fabricated and characterized. In the device fabrication, 2-TNATA [4,4',4'-tris(2-naphthylphenyl-phenylamino)-triphenyl-amine] as a hole injection material and NPB[N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl -4,4'-diamine] as a hole transport material were deposited on the ITO(indium thin oxide)/glass substrate by vacuum evaporation. And then, yellow emission material was deposited using GDI602 as a host material and Rubrene(10%) as a dopant. Finally, small molecular OLED with the structure of $ITO/2-TNATA/NPB/GDI602:Rubrene(10%)/Alq_{3}/LiF/Al$ was obtained by in-situ successive deposition of $Alq_{3}$, LiF and Al as the electron transport material, electron injection material and cathode. The yellow OLED fabricated in our experiments showed the color coordinate of CIE(0.50, 0.49), the luminance of $2300\;Cd/m^{2}$ and the power efficiency of 0.7 lm/W at 10 V with the peak emission wavelength of 562 nm.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.6
• /
• pp.511-514
• /
• 2008

2-wavelength type white OLED devices have been made consisted of two layers; a layer with blue light emitting DPVBi host and other EML layer with yellow emitting rubrene dopant. New method to get white emitting device has been suggested by varying thicknesses of the DPVBi layer. The ITO/2-TNATA($150{\AA}$)/NPB($350{\AA}$)/DPVBi($35{\AA}$)/DPVBi:rubrene (2wt%,$200{\AA}$)/DPVBi($100{\AA}$)/Alq_3($50{\AA}$)/LiF($5{\AA}$)/Al($1000{\AA}$) structure has showed optimum results in CIE coordinates of (0.3233, 0.33). OLED devices with this structure has properties of $1.2d/m^2$ at turn-on voltage of 3.9V and $1037cd/m^2$ at 7.9V. This structure has advantages of simple fabrication and easy to emit the white color.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.7
• /
• pp.616-621
• /
• 2003

The white-light-emitting organic LED with two-wavelength was fabricated using blue emitting material(DPVBi) and a series of orange color fluorescent dye(Rubrene) by vacuum evaporation processes. The basic structure of white-light-emitting OLED was ITO/NPB(150$\AA$)/DPVBi(150$\AA$)/Alq$_3$:Rubrene(150$\AA$)/BCP(100$\AA$)/Alq$_3$(150$\AA$)/Al(600$\AA$). The changes of the CIE coordiante strongly depended on the doping concentration of Rubrene and the thickness of NPB layer. We obtained the white-light-emitting OLED close to the pure white color light and the CIE coordinate of the device was (0.315, 0.330) at applied voltage of 13V when the doping concentration of Rubrene was 0.5wt% and the thickness of NPB layer is 200$\AA$. At a current of 100mA/$\textrm{cm}^2$, the quantum efficiency was 0.35%.

• Applied Chemistry for Engineering
• /
• v.32 no.2
• /
• pp.214-218
• /
• 2021

We investigated the optimal stacked structure from the perspective of process architecture (PA) through emission spectrum analysis according to the wavelength of quantum dot (QD)-organic light-emitting diodes (OLED). We confirmed that the blue-light leakage through the QD can be minimized by increasing the QD filling density above a critical value in the red QD (R-QD) layer. In addition, when the thickness of red-color filter (R-CF) at the upper part of the R-QD increased to more than 3 ㎛, the leakage of blue light through the R-CF was effectively blocked, and a very sharp emission spectrum in the red wavelength band could be obtained. According to these outstanding results, we expect that the development of QD-OLED displays with very excellent color gamut can be possibly realized.

• 전자공학회논문지 IE
• /
• v.45 no.1
• /
• pp.1-6
• /
• 2008

In this paper, the white organic LED with two-wavelength was fabricated using the NPB of blue emitting material and a series of orange color fluorescent dye(Rubrene) by vacuum evaporation processes. The structure of white OLED was ITO/NPB$(200{\AA})$NPB:Rubrene$(300{\AA})$/BCP$(100{\AA})/Alq_3(100{\AA})/Al(1000{\AA})$ and the doping concentration of Rubrene was 0.75 wt%. We obtained the white OLED with CIE color coordinates were x=0.3327 and y=0.3387, and the maximum EL wavelength of the fabricated white organic light-emitting device was 560 nm at applied voltage of 11 V, which was similar to NTSC white color with CIE color coordinates of x=0.3333 and y=0.3333. The turn-on voltage is 1 V, the light-emitting him-on voltage is 4 V. We were able to obtain an excellent maximum external quantum efficiency of 0.457 % at an applied voltage of 18.5 V and current density of $369mA/cm^2$.