Color‐Stable, All‐Phosphorescent White Organic Light Emitting Diodes Using the Polariton‐Enhanced Purcell Effect
- Department of Physics University of Michigan Ann Arbor MI 48109 USA
- Department of Physics University of Michigan Ann Arbor MI 48109 USA, Applied Physics Program University of Michigan Ann Arbor MI 48109 USA, Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI 48109 USA, Department of Materials Science and Engineering University of Michigan Ann Arbor MI 48109 USA
Abstract
The short operational lifetimes of high efficiency phosphorescent organic blue light emitting devices (PHOLEDs) has limited their use in displays and lighting. Previously, this problem has been avoided by using less efficient fluorescent blue devices in separately biased red, green, and blue emissive elements to achieve stable full color emission. However, the operational lifetime of blue phosphorescent OLEDs has been significantly improved through the utilization of the plasmon‐exciton‐polariton‐enhanced (PEP) Purcell effect. Here, a white emitting PHOLED comprising stacked red, green, and blue elements is demonstrated that exploits PEPs to extend the operational lifetime of the blue element such that all emissive layers degrade at the same rate. The device features white light emission with an external quantum efficiency of 19.1 ± 0.4%, luminous power efficiency of 13.3 ± 0.3 lm W −1 at a luminance of 1000 cd m −2 when measured over 4π solid angle, with a color rendering index of 76 unchanged throughout the device aging to 70% of its initial luminance, T 70 . A 2.9 times enhancement in the operational lifetime of the Purcell‐enhanced device is achieved to yield T 70 = 2900 ± 100 h for an initial luminance of 1000 cd m −2 , compared to devices lacking this enhancement with T 70 = 1000 ± 100 h.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- NONE; EE0009688
- OSTI ID:
- 2438644
- Alternate ID(s):
- OSTI ID: 2438645
OSTI ID: 2441280
- Journal Information:
- Advanced Functional Materials, Journal Name: Advanced Functional Materials Journal Issue: 52 Vol. 34; ISSN 1616-301X
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English