Sean Xia

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.

Printable phosphorescent organic light-emitting devices

— A new approach to full-color printable phosphorescent organic light-emitting devices (P2OLEDs) is reported. Unlike conventional solution-processed OLEDs that contain conjugated polymers in the emissive layer, the P2OLEDs emissive layer consists of small-molecule materials. A red P2OLED that exhibits a luminous efficiency of 11.6 cd/A and a projected lifetime of 100,000 hours from an initial luminance of 500 cd/m2, a green P2OLED with a luminous efficiency of 34 cd/A and a projected lifetime of 63,000 hours from an initial luminance of 1000 cd/m2, a light-blue P2OLED with a luminous efficiency of 19 cd/A and a projected lifetime 6000 hours from an initial luminance of 500 cd/m2, and a blue P2OLED with a luminous efficiency of 6.2 cd/A and a projected lifetime of 1000 hours from an initial luminance of 500 cd/m2 is presented.

52.4: Highly Efficient Phosphorescent OLED Lighting Panels for Solid State Lighting

We present a 15 cm × 15 cm PHOLEDTM lighting panel that operates with 50 lm/W efficacy, CRI = 87, CCT = 3055 K and lifetime to LT70 ≅ 10,000 hrs at 1,000 cd/m2. We also present a panel with 58 lm/W efficacy, CRI = 86 and CCT = 2790 K at 1,000 cd/m2, and a small-area lighting pixel with 109 lm/W efficacy, CRI = 80, CCT = 3295 K and lifetime to LT70 ≅ 15,000 hrs at 1,000 cd/m2. A highly stable light blue phosphorescent host-emitter system is used to reduce power consumption, extend operational lifetime and demonstrate exceptional emission color stability with aging.

Ink‐jet‐printable phosphorescent organic light‐emitting‐diode devices

Abstract— A novel method for the fabrication of ink-jet-printed organic light-emitting-diode devices is discussed. Unlike previously reported solution-processed OLED devices, the emissive layer of OLED devices reported here does not contain polymeric materials. The emission of the ink-jet-printed P2OLED (IJ-P2OLED) device is demonstrated for the first time. It shows good color and uniform emission although it uses small-molecule solution. Ink-jet-printed green P2OLED devices possess a high luminous efficiency of 22 cd/A at 2000 cd/m2 and is based on phosphorescent emission. The latest solution-processed phosphorescent OLED performance by spin-coating is disclosed. The red P2OLED exhibits a projected LT50 of >53,000 hours with a luminous efficiency of 9 cd/A at 500 cd/m2. The green P2OLED shows a projected LT50 of >52,000 hours with a luminous efficiency of 35 cd/A at 1000 cd/m2. Also discussed is a newly developed sky-blue P2OLED with a projected LT50 of >3000 hour and a luminous efficiency of 18 cd/A at 500 cd/m2.

Impact of Trapped Charge and Interface Defects on the Degradation of the Optical and Electrical Characteristics in

Electroluminescence degradation mechanisms in small-molecule-based organic light-emitting diodes (OLEDs) have been investigated. We focused on intrinsic degradation phenomena that determine the decrease in the optical power of OLEDs during standard operation. The study was carried out on simplified OLED structures, by means of combined optical and electrical characterization techniques. The results of this analysis provide information on the physical processes responsible for OLED degradation, suggesting a strong correlation between the reduction in the luminance intensity of the devices and the creation of both positive trapped charge and neutral electron traps at the Alq3/NPD interface. The evidence reported in this paper supports the hypothesis that degradation is due to the instability of the cationic Alq3 species.

\hbox{NPD/Alq}_{3}

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.

OLEDs

With this paper we report a comparison of the performance and reliability of Organic Light-Emitting Diodes (OLEDs) with Indium-Tin Oxide (ITO) and Indium-Zinc Oxide (IZO) anode contact layer. The analysis has been carried out by means of electrical and optical measurements: the devices have been compared in terms of efficiency, thermal resistance and reliability. The results of this analysis indicate that: (i) the use of an IZO anode allows to achieve an efficiency comparable to the case of ITO contacts; (ii) devices with IZO contact have a significantly lower thermal resistance, compared to the ones with ITO anode; (iii) accelerated stress tests show that the OLEDs with IZO anode exhibit an higher reliability. Therefore, the relevant results presented within this work demonstrate that the use of IZO anodes guarantees OLED performance comparable with commercial ITO anodes, and allows a better heat dissipation and devices reliability.

Development of phosphorescent OLED lighting panels for highly efficient solid state lighting

This paper reports on a new approach to full-color printable phosphorescent organic light emitting devices (P2OLEDs). Unlike conventional solution processed OLEDs that contain conjugated polymers in the emissive layer, the P2OLEDs emissive layer consists of small molecule hosts and dopants. We present a red P2OLED that exhibits luminous efficiency of 9 cd/A and a projected lifetime of 53,000 hrs from an initial luminance of 500 cd/m2, a green P2OLED with luminous efficiency of 35 cd/A and a projected lifetime 52,000 hrs from an initial luminance of 1000 cd/m2, a light blue P2OLED with luminous efficiencies of 18 cd/A and a projected lifetime 3,000 hrs from an initial luminance of 500 cd/m2, and a blue P2OLED with luminous efficiencies of 6 cd/A and a projected lifetime 1,000 hrs from an initial luminance of 500 cd/m2.