• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1520-1521
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• 2008

There are several ways to demonstrate white organic light emitting diodes (OLEDs) for displays and solid state lighting applications. Among these approaches are the stacked three primary or two complementary colors light-emitting layers, multiple-doped emissive layer, and excimer and exciplex emission [1-10]. We report on white phosphorescent excimer devices by using two light emitting materials based on platinum complexes. These devices showed a peak EQE of 15.7%, with an EQE of 14.5% (17 lm/W) at $500\;cd/m^2$, and a noticeable improvement in both the CIE coordinates (0.381, 0.401) and CRI (81). Devices with the structure ITO/PEDOT:PSS/TCTA (30 nm)/26 mCPy: 12% FPt (10 nm) /26 mCPy: 2% Pt-4 (15 nm)/BCP (40 nm)/CsF/Al [device 1], ITO/PEDOT:PSS/TCTA (30 nm)/26 mCPy: 2% Pt-4 (15 nm)/26 mCPy: 12% FPt (10 nm)/BCP (40 nm)/CsF/Al [device 2], and ITO/PEDOT:PSS/TCTA (30 nm)/26 mCPy: 2% Pt-4: 12% FPt (25 nm)/BCP (40 nm)/CsF/Al [device 3] were fabricated. In these cases, the emissive layer was either the double-layer of 26 mCPy:12% FPt and 15 nm 26 mCPy: 2% Pt-4, or the single layer of 26mCPy with simultaneous doping of Pt-4 and FPt. Device characterization indicates that the CIE coordinates/CRI of device 2 were (0.341, 0.394)/75, (0.295, 0.365)/70 at 5 V and 7 V, respectively. Significant change in EL spectra with the drive voltage was observed for device 2 indicating a shift in the carrier recombination zone, while relatively stable EL spectra was observed for device 1. This indicates a better charge trapping in Pt-4 doped layers [10]. On the other hand, device 3 having a single light-emitting layer (doped simultaneously) emitted a board spectrum combining emission from the Pt-4 monomer and FPt excimer. Moreover, excellent color stability independent of the drive voltage was observed in this case. The CIE coordinates/CRI at 4 V ($40\;cd/m^2$) and 7 V ($7100\;cd/m^2$) were (0.441, 0.421)/83 and (0.440, 0.427)/81, respectively. A balance in the EL spectra can be further obtained by lowering the doping ratio of FPt. In this regard, devices with FPt concentration of 8% (denoted as device 4) were fabricated and characterized. A shift in the CIE coordinates of device 4 from (0.441, 0.421) to (0.382, 0.401) was observed due to an increase in the emission intensity ratio of Pt-4 monomer to FPt excimer. It is worth noting that the CRI values remained above 80 for such device structure. Moreover, a noticeable stability in the EL spectra with respect to changing bias voltage was measured indicating a uniform region for exciton formation. A summary of device characteristics for all cases discussed above is shown in table 1. The forward light output in each case is approximately $500\;cd/m^2$. Other parameters listed are driving voltage (Bias), current density (J), external quantum efficiency (EQE), power efficiency (P.E.), luminous efficiency (cd/A), and CIE coordinates. To conclude, a highly efficient white phosphorescent excimer-based OLEDs made with two light-emitting platinum complexes and having a simple structure showed improved EL characteristics and color properties. The EQE of these devices at $500\;cd/m^2$ is 14.5% with a corresponding power efficiency of 17 lm/W, CIE coordinates of (0.382, 0.401), and CRI of 81.

• 한국식품저장유통학회지
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• 제19권2호
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• pp.235-242
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• 2012

유색미의 영양학적 특성을 알리고, 소비를 촉진하기 위해 전라남도 내에서 생산되는 유색미 5종을 대상으로 영양학적, 이화학적 특성을 조사하였다. 일반성분 중 조단백질의 경우 보성 흑미가 10.15%로 가장 높았고 진도 정미(7.85%)와 녹미(7.57%)가 가장 낮아 도정된 쌀보다 유색미가 전반적으로 높은 함량을 보였으며, 조지방은 모든 시료가 도정된 흑미(1.55%)보다 높게(2.73~3.08%) 나타났다. 유리당의 경우 glucose, fructose, maltose와 mannose가 검출되었으며, maltose는 찰흑미에서, mannose는 흑향미와 적미에서, fructose는 찰흑미, 흑향미에서 높은 결과를 보였다. 무기질의 경우 P, K, Mg, Na, Ca과 Mn 등은 분석 시료에서 고루 함유하고 있었으며, 흑미와 적미가 녹미와 도정된 진도산 흑미에 비해 무기성분 함량이 다소 높은 결과를 보였다. 특히 P (361.32~570.11 mg%), K (196.63~210.04 mg%)과 Mg (104.11~128.02 mg%)는 도정된 정미에 비해 높은 함량을 나타냈다. 지방산 조성은 적미를 제외한 모든 품종에서 linoleic acid가 oleic acid 보다는 더 높게 분석되었으며, 적미에서는 oleic acid가 높게 검출되었다. 구성 아미노산은 보성 흑미, 진도 흑미, 녹미, 적미, 진도 정미 순으로서 보성 흑미가 가장 높게 나타났으며, 특히 녹미는 필수아미노산인 lysine이 996.8 mg%로 높은 함량을 보였다. 쌀의 색도는 낱알에서 L값이 녹미, 진도 정미, 적미, 진도 흑미, 보성 흑미의 순이었고, a값은 적미, 진도 정미, 진도 흑미, 보성 흑미, 녹미 순이며 b값은 녹미, 적미, 진도 정미, 진도 흑미, 보성 흑미 순으로 높게 나타났다. 비타민 $B_1$과 $B_2$는 적미가 각각 0.48 mg/100 g, 0.14 mg/100 g으로 타 시료에 비해 높게 분석되었으며, 시료별 경도는 10.75~14.64 kg/$cm^2$으로 시료간 차이를 보였으며 정미보다는 현미 상태가 더 높은 결과를 보였다.