Phosphorescent OLEDs: Enabling energy‐efficient lighting with improved uniformity and longer lifetime

Abstract

Abstract— In this paper, the design criteria for scaling up from small‐area organic light‐emitting‐diode (OLED) pixels to large‐area OLED light panels is described. Particular focus is placed on using phosphorescent OLEDs (PHOLEDs) to maximize panel efficacy and uniformity and minimize operating temperature. Data for a pair of all‐phosphorescent 15 × 15 cm OLED light panels are also presented: Panel 1 has 62‐lm/W efficacy, CRI = 81, CCT = 3180K, and lifetime to LT70 = 18,000 hours at 1000 cd/m2 and Panel 2 has 58‐lm/W efficacy, CRI = 82, CCT = 2640K, and lifetime to LT70 = 30,000 hours at 1000 cd/m2. Operating at a 3000 cd/m2 (7740 lm/m2), Panel 2 has 49‐lm/W efficacy with lifetime to LT70 = 4000 hours. Excellent panel lifetime is enabled by a stable light‐blue phosphorescent materials system and by the use of efficient phosphorescent emitters that ensure very low panel temperature without any additional thermal management.

O2 /HMDSO-Plasma-Deposited Organic-Inorganic Hybrid Film for Gate Dielectric of MgZnO Thin-Film Transistor

“…Recently, this organic–inorganic hybrid material has been applied to large‐area electronics . Mandlik et al first applied a hybrid film deposited from an HMDSO and O 2 mixture to the encapsulation of OLEDs; the lifetime of the OLEDs was significantly improved. Han et al from the same group further used this hybrid film as the gate dielectric of a‐Si:H TFTs .…”

“…The chemical compositions can vary from polymer‐like (organic‐like) to SiO 2 ‐like (inorganic‐like) depending on the oxidant dilution ratio and the process power; therefore, the required material can be specifically designed for a particular application. Owing to this feature, hybrid films produced by this technique find various applications such as corrosion protection coatings for metals, food packaging, interfacial medium coatings for biomaterials, permeation barriers for organic light emitting diodes (OLEDs), and gate dielectrics for hydrogenated amorphous silicon thin‐film transistors (a‐Si:H TFTs) …”

The study of the effect on the organic emitting diodes with (t-bt)2Ir(acac) as deep hole-trap

“…Especially the phosphorescent OLEDs, due to efficient use of the triplet excitons for electroluminescence 2 , could achieve extremely high luminance and efficiency for OLEDs commercialization. Commonly phosphorescent emitting materials were doped in suitable host materials, which could reduce the concentration quenching to receive high luminance and efficiency [3][4][5] .…”

Color Stability of Blue Phosphorescent Organic Light-Emitting Diodes with Undoped Layer in Emissive Layer

“…Therefore, some researchers have suggested new structures and materials. 6,[15][16][17][18][19][20][21] However, most studies have been focused on increasing efficiency, not lifetime; but lifetime is a crucial issue in the commercialization of blue phOLEDs. Also, the color of a blue phOLED has to be maintained uniformly during driving, but in most devices, their color changes owing to degradation.…”