Huiqing Pang

Phosphorescent organic light-emitting diodes for high-efficacy long-lifetime solid-state lighting

We report data for a pair of singlestack all-phosphorescent 15 × 15 cm 2 organic light emitting-diode (OLED) light panels with high efficacy, long lifetime, and very low operating temperature: Panel 1 has 62 lm∕W efficacy, CRI ¼ 81 and lifetime to LT70 ¼ 18;000 h at 1000 cd∕m 2 , while Panel 2 has 58 lm∕W efficacy, CRI ¼ 82 and lifetime to LT70 ¼ 30;000 h at 1000 cd∕m 2 . Operating at a higher luminance of 3000 cd∕m 2 , Panel 2 has 49 lm∕W efficacy with lifetime to LT70 ¼ 4000 h. Excellent panel lifetime is enabled by a stable light blue phosphorescent materials system. Panel temperatures are within 10°C of ambient temperature at 3000 cd∕m 2 . Panel 2 was further used as a building block to demonstrate an all-phosphorescent OLED luminaire for under-cabinet lighting applications. Operating at approximately 3000 cd∕m 2 , theluminairedelivers570lmwith52 lm∕Wtotalsystemefficacy,CRI ¼ 86andCCT ¼ 2940 K.© 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). (DOI: 10.1117/1.JPE.2.021205)

72.2: Phosphorescent OLEDs: Enabling Solid State Lighting with Lower Temperature and Longer Lifetime

We present a pair of 15 cm × 15 cm all-phosphorescent OLED light panels with high efficacy and extended operational lifetime. Panel 1 operates at 1,000 cd/m2 with power efficacy = 62 lm/W. At a higher luminance of 3,000 cd/m2, power efficacy = 49 lm/W, CRI = 82, CCT = 2,950 K and CIE 1931 (x, y) = (0.446, 0.417). Similar high efficacy performance is recorded for Panel 2, which has lifetime to LT70 ∼ 4,000 hrs at 3,000 cd/m2. Excellent lifetime is enabled by a new light blue phosphorescent materials system and by the use of efficient phosphorescent emitters that ensure very low panel temperature without any additional thermal management.

66.4: Invited Paper: Challenges and Opportunities in Scaling Up OLED Lighting Devices

In this paper we discuss the challenges involved in scaling from small size pixels to large area OLED lighting panels, with specific focus on panel luminance uniformity, resistive loss and lifetime. We also discuss panel design and report results for a 15 cm × 15 cm phosphorescent OLED (PHOLED) lighting panel.

Recent progress of flexible AMOLED displays

Significant progress has been made in recent years in flexible AMOLED displays and numerous prototypes have been demonstrated. Replacing rigid glass with flexible substrates and thin-film encapsulation makes displays thinner, lighter, and non-breakable - all attractive features for portable applications. Flexible AMOLEDs equipped with phosphorescent OLEDs are considered one of the best candidates for low-power, rugged, full-color video applications. Recently, we have demonstrated a portable communication display device, built upon a full-color 4.3-inch HVGA foil display with a resolution of 134 dpi using an all-phosphorescent OLED frontplane. The prototype is shaped into a thin and rugged housing that will fit over a users wrist, providing situational awareness and enabling the wearer to see real-time video and graphics information.

Large-area high-efficiency flexible PHOLED lighting panels

Organic Light Emitting Diodes (OLEDs) provide various attractive features for next generation illumination systems, including high efficiency, low power, thin and flexible form factor. In this work, we incorporated phosphorescent emitters and demonstrated highly efficient white phosphorescent OLED (PHOLED) devices on flexible plastic substrates. The 0.94 cm2 small-area device has total thickness of approximately 0.25 mm and achieved 63 lm/W at 1,000 cd/m2 with CRI = 85 and CCT = 2920 K. We further designed and fabricated a 15 cm x 15 cm large-area flexible white OLED lighting panels, finished with a hybrid single-layer ultra-low permeability single layer barrier (SLB) encapsulation film. The flexible panel has an active area of 116.4 cm2, and achieved a power efficacy of 47 lm/W at 1,000 cd/m2 with CRI = 83 and CCT = 3470 K. The efficacy of the panel at 3,000 cd/m2 is 43 lm/W. The large-area flexible PHOLED lighting panel is to bring out enormous possibilities to the future general lighting applications.