High color rendering white organic light-emitting diodes fabricated using a broad-bandwidth red phosphorescent emitter for lighting applications

Xu, F.; Lim, Jong Min; Kim, Hee Un; Mi, Dongbo; Lee, Jun Yeob; Joo, Chul Woong; Cho, Nam Sung; Lee, Jeong Ik; Hwang, Do‐Hoon

doi:10.1016/j.synthmet.2012.11.025

Cited by 8 publications

(1 citation statement)

References 31 publications

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“…The single and multiple emissive layer (EML) OLED structures have shown important advantages, such as simple device configuration and time-efficient process due to their total organic thickness of about 100–150 nm. − Indeed, the viewing angle characteristics of such devices are less affected by relatively weak optical interference because of the short distance between the light emissive layer and the reflective electrode. However, these thin OLEDs are sensitive to the particles and surface roughness and also exhibit short operational lifetimes.…”

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confidence: 99%

Optical Design and Optimization of Highly Efficient Sunlight-like Three-Stacked Warm White Organic Light Emitting Diodes

et al. 2017

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In this paper, we report an optical structure design method with the predicted performances of highly efficient three-stacked white organic light emitting diodes (WOLEDs) for solid state lighting applications. The efficiency and color properties of stacked WOLEDs are strongly affected by optical interference inside the thick cavity length; therefore appropriate emissive layer (EML) position is determined by thorough theoretical optical simulations to prevent such optical effect. The theoretically evaluated, three-stacked hybrid WOLED with entirely separated phosphorescent red and green as well as fluorescent blue EML has displayed a CRI and power efficiency of 91 and 33.5 lm/W, respectively. Based on our assumptions, design method, and optical simulation results, the fabricated three-stacked WOLEDs showed a CRI of 93, external quantum efficiency (EQE) of 49.4%, and power efficiencies of 33.4 lm/W. These experimentally measured characteristics are fully correlated with the performances of optically simulated devices. It is important to note that the driving voltage (10.0 V) of optically designed WOLEDs is almost identical to the summation of unit devices (9.9 V) because of good interconnecting units and the same charge balance in the tandem WOLEDs. In addition, the experimentally measured power efficiency of the tandem device is similar to an average value of the unit devices, and most importantly the EQE is nearly equal to the summation of the unit devices with an almost matched white spectrum.

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