Brian D'Andrade

Efficient, deep-blue organic electrophosphorescence by guest charge trapping

We demonstrate efficient, deep-blue organic electrophosphorescence using a charge-trapping phosphorescent guest, iridium(III) bis(4′,6′-difluorophenylpyridinato)tetrakis(1-pyrazolyl)borate (FIr6) doped in the wide-energy-gap hosts, diphenyldi(o-tolyl)silane (UGH1) and p-bis(triphenylsilyly)benzene (UGH2), where exciton formation occurs directly on the guest molecules. Charge trapping on the guest is confirmed by the dependence of the drive voltage and electroluminescence spectrum on guest concentration. Ultraviolet photoemission spectroscopy measurements establish the relative highest occupied molecular orbital positions of FIr6 in UGH1 and UGH2. Peak quantum and power efficiencies of (8.8±0.9)% and (11.0±1.1) lm/W in UGH1 and (11.6±1.2)% and (13.9±1.4) lm/W in UGH2 are obtained, while the emission in both cases is from FIr6 and is characterized by Commission Internationale de l’Eclairage coordinates of (x=0.16, y=0.26) in UGH2.

Realizing white phosphorescent 100 lm/W OLED efficacy

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.

White phosphorescent organic light emitting devices

OLED display manufacturers are interested in white organic light emitting devices (WOLEDs) 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/m normal luminance, EQE = 35%, power efficacy is 62 lm/W, operating voltage = 4.4 V, CIE = (0.33, 0.43) and CRI = 70.

19.3: Efficient White Phosphorescent Organic Light‐Emitting Devices

We demonstrate two phosphorescent white OLEDs. At 1,000 cd/m2, one has EQE = 20% at CIE = (0.38, 0.39), and another has 25 lm/W with CIE (0.39, 0.44). At 100 cd/m2 and with outcoupling enhancements, devices either have total EQE = 37% or total efficacy = 51 lm/W.

11.1: Invited Paper: Advances in Blue Phosphorescent Organic Light-Emitting Devices

paper discusses the latest developments towards a commercial blue phosphorescent organic light emitting device (PHOLED™) technology. Progress towards achieving a high efficiency, long-lived saturated blue PHOLED is discussed. First, a high efficiency (20% EQE, 45 cd/A), light blue (0.17, 0.39) PHOLED is presented. Next, long-lived blue PHOLEDs having chromaticity co-ordinates (0.17, 0.38) and (0.16, 0.29) are estimated to degrade to half their initial luminance of 200cd/m 2 after >100,000 hrs and 17,500 hrs, respectively. Finally, results from PHOLEDs designed to increase blue color saturation and lifetime are presented. 1. Introductiont organic light emitting devices (PHOLEDs) (1), the singlet excited state (S1) excitons may be converted into the triplet excited state (T1) through inter-system crossing via the presence of a heavy metal atom. In these devices, the triplet states can emit radiatively (T1 to S0), enabling record high conversion efficiencies. The first generation of PHOLEDs contained platinum 2,3,7,8,12,13,17,18-octaethyl-12H,23H-porphyrin (PtOEP) as the dopant phosphor. An impressive external quantum efficiency, at the time, of 6% was reported (2).

61.5L: Late-News Paper: Extremely Long Lived White Phosphorescent Organic Light Emitting Device with Minimum Organic Materials

A non-stacked white phosphorescent organic light emitting device with 6 organic materials is demonstrated with extremely long lifetime of LT50 >200,000 hrs from 1,000 nits initial luminance. At 1,000 nits without enhanced outcoupling, EQE = 15.3% (32.4 cd/A), operating voltage = 6.3 V, power efficacy = 16.1 lm/W (30 lm/W with outcoupling enhancement), and CIE (0.45, 0.46).

Highly power efficient organic light-emitting devices enabled by phosphorescent and p-i-n technologies

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.

Comparison of blue-emitting phosphorescent dopants: effect of molecular energy levels on device efficiency

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.

27.2: Single Dopant p‐i‐n White Organic Light Emitting Devices

We demonstrate efficient, low operating voltage white organic light-emitting devices (WOLEDs) employing an emissive region containing a single phosphorescent dopant, platinum(II)(2-(4′,6′-difluorophenyl)pyridinato-N, C2′)(2,4-pentanedionato). The WOLED exhibited peak external quantum and power efficiencies of (4.8±0.5)% and (11±1.0)lm/W, respectively, and had color coordinates of (0.34, 0.43) and a color rendering index value of 71.

White PHOLED for Lighting

At 1,000 cd/m², plusmn white phosphorescent OLED (0.39, 0.44) has forward EQE = 14.5%, and efficacy = 25 Im/W. At 100 cd/m², the device has total EQE = 25% or total efficacy = 51 Im/W.