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.
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.
Consumer display manufacturers are increasingly interested in white organic light emitting devices (WOLEDs), because
these devices offer thinner display profiles, and in combination with color filters eliminate the need for high-resolution
shadow masks. Additionally, WOLEDs are well suited for general-purpose illumination, since the power efficiencies of
laboratory devices have surpassed that of today's commercial incandescent bulbs. In this paper, we report on an all
phosphorescent 25 cm2 WOLED lighting system that achieves (31±3) lm/W at 850 cd/m2 with CIE coordinates (0.37,
0.36), and an external quantum efficiency of (29±3)%.
Organic light-emitting devices (OLEDs) containing highly efficient phosphorescent emitters and highly conductive
doped organic transport layers were studied. Saturated red devices with luminous efficiency of 15 cd/A operate at <4 V;
hence, they have a record power efficiency of 12 lm/W at 1,000 cd/m2.
Additionally, two high-efficiency red OLEDs were serially connected and vertically stacked to create a stacked OLED
having a luminous and power efficiency (at 1,000 cd/m2) of 28 cd/A and 12 lm/W, respectively. The electrical
connection between the two OLEDs is enabled by molecular p- and n-type doped organic transport layers.
The single emissive layer red OLED has a projected lifetime (time to half initial luminance) of ~150,000 hrs from an
initial brightness of 500 cd/m2. The stacked device shows very similar lifetime characteristics when driven at similar
currents, which results in significantly prolonged lifetime of ~260,000 hrs at an initial luminance of 500 cd/m2.
Consumer display manufacturers are increasingly interested in white organic light emitting devices (WOLEDs), because these devices offer thinner display profiles, and in combination with color filters eliminate the need for shadow masks. Additionally, WOLEDs are well suited for general-purpose illumination, and laboratory results show that their power efficiencies have surpassed that of incandescent bulbs. To replace current backlight technologies with WOLEDs, further increases must be made in the power efficiency of blue and red phosphorescent devices, and in the power density of OLEDs. In this paper, we report on a blue-red-green 6" square striped lighting panel emitting >100 lumens, and on a stacked OLED (SOLED) 6" square panel. The SOLED consists of a red and green OLED connected by a 70 nm- thick aluminum electrode that simultaneously serves as the cathode for the bottom green device and as the anode for the top red device.
A 6"x6" white lighting panel consisting of red, green and blue colored stripes of OLEDs emits >100 lm of optical power and has a maximum energy efficacy of 30 lm/W. Each colored stripe contains 7 serially connected OLEDs having an area of 1.37 cm2, and there are 4 stripes per color, so there is a total of 84 devices. The external quantum efficiency of the red and blue OLEDs exceeds 20% and the blue OLED efficiency exceeds 5% when operated above 100 nits. Such high quantum efficiencies are achieved with an OLED architecture consisting of electrophosphorescent dopants, and at least four organic thin films layers: a hole injection layer, a hole transport layer, an emissive layer, a blocking layer, and an electron transport layer. The color coordinates of the panel can be varied between the constituent red, green, and blue color component coordinates of (0.14, 0.17), (0.31, 0.64), and (0.62, 0.38), respectively, by adjusting the intensity of each primary colors. Panel power efficiencies were measured at correlated color temperatures between 2,900 K and 5,700K, and the color rendering index was >80 in all cases because of the broad spectral output of the combined colors.
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.
We demonstrate efficient (ηp=11±1 lm/W at 1000 cd/m2), bright electrophosphorescent white organic light emitting devices (WOLEDs) employing three dopants in a 9-nm-thick inert host matrix. The emissive layer consists of 2 wt.% iridium (III) bis(2-phenyl quinolyl-N,C2') acetylacetonate (PQIr), 0.5 wt.% fac-tris(2-phenylpyridine) iridium (Ir(ppy)3) and 20 wt.% bis(4’,6’-difluorophenylpyridinato)tetrakis(1-pyrazolyl)borate (FIr6) co-doped into a wide energy gap p-bis(triphenylsilyly)benzene (UGH2) host. Devices were characterized in terms relevant to both display and general lighting applications, and have a peak total power efficiency of 42±4 lm/W at low intensities, falling to 10±1 lm/W at a drive current of 20 mA/cm2 (corresponding to 1.4 lm/cm2 for an isotropic illumination source). The Commission Internationale de l’Eclairage coordinates shift from (0.43,45) at 0.1 mA/cm2 to (0.38,0.45) at 10 mA/cm2, and a color rendering index >75 is obtained. Three factors contribute to the high efficiency: thin layers leading to low voltage operation, a high quantum efficiency blue dopant, and efficient confinement of charge and excitons within the emissive region. The highest occupied and lowest unoccupied energy levels of component layers will be discussed to elucidate charge and exciton confinement within the emissive layer. Additionally, we will explain energy transfer between dopants based on photoluminescent transient analysis of triple-doped thin films.