We report data for a pair of singlestack all-phosphorescent 15×15 cm2 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 = 81 and lifetime to LT70 = 18,000 h at 1000 cd/m2, while Panel 2 has 58 lm/W efficacy, CRI = 82 and lifetime to LT70 = 30,000 h at 1000 cd/m2. Operating at a higher luminance of 3000 cd/m2, Panel 2 has 49 lm/W efficacy with lifetime to LT70 = 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/m2. 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/m2, the luminaire delivers 570 lm with 52 lm/W total system efficacy, CRI = 86 and CCT = 2940 K.
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/m2, 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/m2 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/m2.
We present a 7.5 cm x 7.5 cm white PHOLEDTM lighting panel that delivers 1,000 cd/m2 with 68 lm/W
efficacy, CRI > 80 and lifetime to LT70 ≈ 15,000 hrs. A simple all-phosphorescent device architecture,
including a highly stable light blue phosphorescent emitter-host system, is used to reduce panel power
consumption, extend operational lifetime and demonstrate exceptional emission color stability with aging.
OLED display manufacturers are interested in white organic light emitting devices (WOLEDTMs) because these devices, together with color filters, eliminate the need for high resolution shadow masks. Additionally, WOLEDs are well suited for
general-purpose illumination, since their power efficacies are approaching fluorescent lamps. A new structure was developed that had the following characteristics that were measured using a spot meter: at 100 cd/m2 normal luminance, EQE = 20%, power efficacy is 34 lm/W, operating voltage = 3.6 V, CIE = (0.44, 0.44) and CRI = 75.
Phosphorescent organic light emitting device (PHOLEDTM) technology has demonstrated record high efficiencies and
long operational stability. Here we report on the introduction of an additional charge transporting dopant into the device
emissive layer to further improve the luminous efficiency and device lifetime. The performance enhancement is
attributed to the separation of polarons and excitons in the device emissive layer, which results in reduced triplet-triplet
and triplet-polaron interactions as well as minimizing self quenching and reabsorption. Specifically we report a 50%
improvement in the luminous efficiency of a red PHOLED and a 3 fold improvement of the device lifetime due to the
use of dual doping. A dual doped sRGB red device with 28 cd/A and the lifetime over 300,000h at 1,000 nits is
In this paper, two approaches are demonstrated to narrow phosphorescent OLED (PHOLED) emission lineshapes to
increase color saturation while keeping device high efficiency performance, which is critical for large area flat panel
displays. One approach uses bottom-emissive microcavity structure in green and blue devices to achieve 22 nm full
width half maximum (FWHM) emissions. The other approach is to reduce the natural width of the emission as
exemplifying in a red device. A new NTSC red with 64 nm FWHM emission is reported. In a standard device, it has a
luminous efficiency of 18.3 cd/A at 10 mA/cm2.
OLED display manufacturers are interested in white organic light emitting devices (WOLEDTMs) because
these devices, together with color filters, eliminate the need for high resolution shadow masks, and are
scalable beyond Gen 4 substrates. Additionally, WOLEDs are well suited for general-purpose illumination,
since their power efficacies are approaching fluorescent lamps. A new structure was developed that had the
following characteristics that were measured using a 20" integrating sphere: at 100 cd/m2 normal luminance,
EQE = 35%, power efficacy is 62 lm/W, operating voltage = 4.4 V, CIE = (0.33, 0.43) and CRI = 70.
As organic light emitting device (OLED) technology is building up momentum in the commercial marketplace,
phosphorescent OLEDs (PHOLEDsTM) are proving themselves to be an ideal display medium for a wide range of
product applications: from small mobile displays to large area TVs. As part of this work we continue to advance
PHOLED technology by new materials design and device architectures. For example a green PHOLED with 4.3 V,
70 cd/A, 50 lm/W and > 10,000 hours lifetime at 1,000 cd/m2 is reported. PHOLEDs enable very low power
consumption displays with low display operating temperatures, and can be deposited by a range of different
deposition techniques. Along with state-of-the-art device performance we report results on the ruggedness of
PHOLED materials in high volume manufacturing environments.
Two blue-shifted iridium phenyl-pyridine dopants are compared in identical device structures. While the dopants have very similar optical behavior, it is found that the device efficiencies are very different and dependent on the host material. Upon comparison of molecular energy levels it is proposed that the electronic properties of the dopant influence the device efficiency through an electron trapping mechanism. It is believed that the relative energetics between the host and dopant play an integral role in the operation of the device.
In this paper we describe the applications and status of OLED technology to produce displays ideally suited for mobile applications. In particular, we focus on phosphorescent OLED (PHOLED) technology to reduce display power consumption and flexible OLED (FOLED) technology to reduce the display thickness and weight. We show that PHOLED displays can consume less power than an equivalent backlit AMLCD, and have excellent visual performance characteristics which make these displays highly desirable for portable communication devices. We will then describe an example of a unique communication device, a Universal Communication Device (UCD), based on flexible PHOLED technology, to produce a powerful communication device with a low power consumption and a light weight and very portable form factor. This device, enabled by a roll-out phosphorescent active-matrix display fabricated on a metallic or plastic substrate, is of great interest for a range of both consumer and military products.
Organic light emitting devices (OLEDs) are viewed as a potential next generation lighting source. Phosphorescent OLED (PHOLED) technology, with its inherently high efficiencies, represents the best opportunity to meet the challenging requirements of lighting. We discuss the requirements of OLEDs for lighting applications and present the state-of-the-art of white PHOLEDs, which have demonstrated the luminous efficiencies exceeding 30 cd/A at CIE coordinates of (0.35, 0.33).
In this paper we will outline the technical challenges and progress towards enabling a novel communication device based on a roll-out, low power consumption, OLED display. Advanced mobile communication devices require a bright, high information content display in a small, light-weight, low power consumption package. We believe that phosphorescent OLED (PHOLED) technology fabricated on a truly flexible substrate, enables a mobile Universal Communication Device (UCD) to offer a high information content display in an extendable form, while rolling up into a small form factor when not in use. This communication device is of great interest for a range of both consumer and military applications. From the display perspective, the key component is achieving a long-lived, low power consumption display. We believe the OLEDs are the preferred display media, and in this talk we will outline our flexible phosphorescent OLED technology. The key to reliable operation is to ensure that the organic materials are fully encapsulated in a package designed for repetitive flexing. UDC has been developing long-lived flexible OLED (FOLED) displays based on plastic substrates and multi-layer monolithic encapsulation. Recent progress in this area will also be reported. Finally, we will outline the backplane requirements for flexible OLED displays and compare the various technology options that can be used to fabricate the UCD.
High-efficiency electrophosphorescent organic light emitting devices (OLEDs), based on triplet emission, is an enabling technology for low power full-color OLED displays. In addition, top emission OLED architectures can be used to maximize display aperture ratio and pixel current densities. In this paper we report on recent results in red, green and blue phosphorescent and top emission OLEDs and discuss the benefits that these attributes have on both active and passive matrix display performance.
Organic light emitting diodes (OLEDs) have recently entered the market place as a competitive flat panel display technology. OLED displays are moving rapidly from small passive matrices (i.e. <3 inches diagonal) to full color active matrices based on rigid substrates. This paper is focused on new developments to help enable flexible OLED (FOLED) displays. Presented here will be high efficiency phosphorescent OLED displays that can be used in either passive or active matrix drive configurations. Passive matrix displays incorporating this technology fabricated on flexible substrates are also reported. These early demonstrations of flexible OLED displays illustrate the promise for a whole new generation of display products based on the design dimension of flexibility.
Organic light emitting device (OLED) technology has recently been shown to demonstrate excellent performance and cost characteristics for use in numerous flat panel display (FPD) applications. OLED displays emit bright, colorful light with excellent power efficiency, wide viewing angle and video response rates. OLEDs are also demonstrating the requisite environmental robustness for a wide variety of applications. OLED technology is also the first FPD technology with the potential to be highly functional and durable in a flexible format. The use of plastic and other flexible substrate materials offers numerous advantages over commonly used glass substrates, including impact resistance, light weight, thinness and conformability. Currently, OLED displays are being fabricated on rigid substrates, such as glass or silicon wafers. At Universal Display Corporation (UDC), we are developing a new class of flexible OLED displays (FOLEDs). These displays also have extremely low power consumption through the use of electrophosphorescent doped OLEDs. To commercialize FOLED technology, a number of technical issues related to packaging and display processing on flexible substrates need to be addressed. In this paper, we report on our recent results to demonstrate the key technologies that enable the manufacture of power efficient, long-life flexible OLED displays for commercial and military applications.
Today organic light emitting diodes (OLEDs) are entering the market lace as a competitive flat panel display technology. Rapidly OLED displays are moving from small passive matrices to full color active matrices built on conventional indium tin oxide coated glass. The work in this paper is focused on developing high resolution full color displays on flexible substrates. Presented here will be new developments in high efficiency OLED displays with the application of this technology to flexible substrates thus allowing a whole new generation of display concepts to be realized.
We describe a flexible, transparent plastic substrate for OLED display applications. A flexible, composite thin film barrier is deposited under vacuum onto commercially available polymers, restricting moisture and oxygen permeation rates to undetectable levels using conventional permeation test equipment. The barrier is deposited under vacuum in a process compatible with conventional roll- coating technology. The film is capped with a thin film of transparent conductive oxide yielding an engineered substrate (BarixTM) for next generation, rugged, lightweight or flexible OLED displays. Preliminary tests indicate that the substrate is sufficiently impermeable to moisture and oxygen for application to moisture-sensitive display applications, such as organic light emitting displays, and is stable in pure oxygen to 200 degrees Celsius.
The current-voltage characteristics of ITO/polymer film/Al or Au devices of poly(phenylene vinylene) (PPV) and a dialkoxy PPV copolymer can be fitted at high applied bias to a power law of the form J equals KVm where m increases with decreasing temperature, log(K) is proportional to m, and K is proportional to d-(alpha m) where d is the film thickness and (alpha) is a constant. (alpha) 2 and 1 for the Al and Au cathode devices respectively. Different single carrier space charge limited conduction (SCLC) theories, including either an exponential trap distribution or a hopping transport field and temperature dependent mobility, are used to try and explain this behavior. Both models are in good agreement with the general experimental results, but can also be criticized on a number of specific issues.Mixed SCLC models and the effect of dispersive transport are also explored. It is concluded that carrier mobility and trap measurements are required to distinguish between these models. To this end, initial trap measurements of ITO/PPV/Al devices using deep level transient spectroscopy (DLTS) are reported. Very deep positive carrier transport with emptying times > 4 minutes have been detected. The non-exponential DLTS transients have been successfully modeled on an isoelectronic trap level emptying to a Gaussian distribution of transport states, with a trap depth and density of 0.8eV and 4 by 1016 cm-3 respectively.
We report studies focusing on the nature of trap states present in single layer ITO/polymer/metal devices of poly(p- phenylene vinylene) and its soluble derivative poly(2,5- dialkoxy-p-phenylene vinylene). In the high applied bias regime the IV characteristics from 11 to 290K can be successfully modeled by space charge limited current (SCLC) theory with an exponential trap distribution, giving a trap density of between 1018 and 4 X 1017 cm-3 and a characteristic energy Et of 0.15 eV. Measured conductance transients of PPV are non-exponential and follow a power-law relationship with time whose decay rate decreases with decreasing temperature. This can be directly related to the emptying of the trap distribution deduced from the SCLC analysis. Due to variations in structure, conformation and environment, the polymer LUMO and HOMO density of states form a Gaussian distribution of chain energy sites. The sites involved in carrier transport are those towards the center of the distribution. The deep sites in the tail of the distribution in the carrier energy gap are the observed traps for both positive and negative carriers. The same deep sites dominate the photo- and electroluminescence emission spectra. The model implies that the emissive material in organic light emitting diodes should be made as structurally disordered as possible.