Search

The article describes the design criteria for large-area organic light-emitting-diode (OLED) light panels, with emphasis on the use of phosphorescent OLEDs (PHOLED) to maximize panel efficiency and uniformity. The design rules for reducing the potential drop across 15x15-centimeter OLED light panels are discussed. The article demonstrates that using phosphorescent emitters with 100 percent internal quantum efficiency (IQE) create panels with high efficacy and aperture ratio.

We describe encapsulated passive matrix, video rate organic light-emitting diode (OLED) displays on flexible plastic substrates using a multilayer barrier encapsulation technology. The flexible OLED (FOLED[SUPTM]) displays are based on highly efficient electrophosphorescent OLED (PHOLED[SUPTM]) technology deposited on barrier coated plastic (Flexible Glass[SUPTM] substrate) and are hermetically sealed with an optically transmissive multilayer barrier coating (Barix[SUPTM] encapsulation). Preliminary lifetime to half initial luminance (L[SUB0] ∼ 100 cd/m[SUP2]) of order 200 h is achieved on the passive matrix driven encapsulated 80 dpi displays; 2500 h lifetime is achieved on a dc tested encapsulated 5 mm[SUP2] FOLED test pixel. The encapsulated displays are flexed 1000 times around a 1 in. diameter cylinder and show minimal damage. [ABSTRACT FROM AUTHOR]

Electrophosphorescent devices with fac-tris(2-phenylpyridine)iridium as the green emitting dopant have been fabricated with a variety of hole and exciton blocking materials. A device with aluminum(III)bis(2-methyl-8-quinolinato)4-phenylphenolate (BAlq) demonstrates an efficiency of 19 cd/A with a projected operational lifetime of 10 000 h, operated at an initial brightness of 500 cd/m²; or 50 000 h normalized to 100 cd/m². An orange-red electrophosphorescent device with iridium(III) bis(2-phenylquinolyl-N, C[sup 2')acetylacetonate as the dopant emitter and BAlq as the hole blocker demonstrates a maximum efficiency of 17.6 cd/A with a projected operational lifetime of 5000 h at an initial brightness of 300 cd/m²; or 15 000 h normalized to 100 cd/m². The average voltage increase for both devices is <0.3 mV/h. The device operational lifetime is found to be inversely proportional to the initial brightness, typical of fluorescent organic light emitting devices. [ABSTRACT FROM AUTHOR]