Alexey Borisovich Dyatkin

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.

High-performance phosphorescent white-stacked organic light-emitting devices for solid-state lighting

In this work we report exceptional efficacy, lifetime and color stability for all-phosphorescent white stacked organic light-emitting devices (SOLED®s). We report data for all-phosphorescent white SOLED pixels with two emissive units connected in series by a charge generation layer (CGL). At 3,000  cd/m 2 , efficacy = 54 to 56  lm/W and lifetime to 70% of initial luminance LT70 ≈ 20,000  h, with color rendering index (CRI) = 82 to 83 and chromaticity meeting Energy Star criteria. We further report data for a 15  cm×15  cm white SOLED panel that operates at 3,000  cd/m 2 with 48  lm/W efficacy, CRI = 86 and chromaticity meeting Energy Star criteria. The panel has extremely low operating temperature that is only 6.4°C above ambient, and exceptional lifetime of LT70 ≈ 13,000  h when operated at 3,000  cd/m 2 .

All-phosphorescent white stacked organic LEDs for solid-state lighting

The global lighting industry is in transition. Inefficient light sources, such as the incandescent bulb, are being replaced by energy-efficient alternatives. Solid-state lighting in the form of LEDs and organic LEDs (OLEDs) offers a promising solution. Here, we focus on OLED lighting, which is a rapidly accelerating technology that offers power-efficient, high-quality illumination with unprecedented form factors (e.g., minimal thickness, flexibility, and transparency), and low operating temperatures. However to meet the demands of mainstream lighting applications, improvement in OLED device lifetime is still required. It is customary to report lifetimes for solid-state lighting (SSL) based on the time taken for emission to decay to 70% of initial luminance (LT70). The longest lifetime reported to date for a single-unit warm white phosphorescent organic LED (PHOLEDTM) pixel is LT70 55; 000h at an initial luminance of 1000cd/m2 for a 2mm2 pixel with 72lm/W efficacy and colorrendering index .CRI/ D 85.1 (Lumen, lm, is a measure of luminous flux. Candela, cd, is a measured of luminous intensity.) Although the lifetime of single-unit phosphorescent OLEDs is already extremely encouraging, here we describe an approach to further enhance device lifetime by stacking OLEDs so that light from two stacks can be combined without any need to increase the area of the light source. In this stacked OLED (SOLED) configuration, we separate emissive units by a charge-generation layer (CGL) that serves as an anode for one unit and as a cathode for a second unit.2, 3 SOLEDs offer longer operational lifetime than equivalent single-unit OLEDs because the required luminance from each unit is reduced for a given total light output. For example, where we have two units in a SOLED stack, each need Figure 1. Blue/red-green (B/RG) stacked organic LED (SOLED) architecture (device 1: left), red-green-blue/red-green-blue (RGB/RGB) SOLED architecture (device 2: right). BL: Blocking layer. CGL: Charge-generation layer. EML: Emission layer. ETL: Electron transport layer. HIL: Hole (positive charge carrier) injection layer. HTL: Hole transport layer. ITO: Indium tin oxide.