Low driving voltage white organic light-emitting diodes with high efficiency and low efficiency roll-off

Zhang, Zhensong; Yan, Pingrui; Yue, Shouzhen; Yu, C. X.; Wu, Qingwen; Qu, Dalong; Guo, Runda; Wang, Peng; Zhao, Yi; Liu, Shiyong

doi:10.1016/j.orgel.2013.05.024

Cited by 19 publications

(15 citation statements)

References 40 publications

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“…At 100 and 1000 cd m −2 , the voltages are 3.0 and 3.95 V, respectively. As it is still a challenge for WOLEDs to achieve low driving voltages for practical use (e.g., <3 V for onset and <4 V at 100 cd m −2 for portable displays) [ 43 ], it is clear that our device can effectively alleviate this difficulty. It is important to note that a much higher efficiency and lower voltage can be expected if a p-i-n structure is used.…”

Section: Discussion and Resultsmentioning

confidence: 99%

Regulating Charge and Exciton Distribution in High-Performance Hybrid White Organic Light-Emitting Diodes with n-Type Interlayer Switch

et al. 2017

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The interlayer (IL) plays a vital role in hybrid white organic light-emitting diodes (WOLEDs); however, only a negligible amount of attention has been given to n-type ILs. Herein, the n-type IL, for the first time, has been demonstrated to achieve a high efficiency, high color rendering index (CRI), and low voltage trade-off. The device exhibits a maximum total efficiency of 41.5 lm W−1, the highest among hybrid WOLEDs with n-type ILs. In addition, high CRIs (80–88) at practical luminances (≥1000 cd m−2) have been obtained, satisfying the demand for indoor lighting. Remarkably, a CRI of 88 is the highest among hybrid WOLEDs. Moreover, the device exhibits low voltages, with a turn-on voltage of only 2.5 V (>1 cd m−2), which is the lowest among hybrid WOLEDs. The intrinsic working mechanism of the device has also been explored; in particular, the role of n-type ILs in regulating the distribution of charges and excitons has been unveiled. The findings demonstrate that the introduction of n-type ILs is effective in developing high-performance hybrid WOLEDs.

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Section: Discussion and Resultsmentioning

confidence: 99%

Regulating Charge and Exciton Distribution in High-Performance Hybrid White Organic Light-Emitting Diodes with n-Type Interlayer Switch

et al. 2017

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“…At 100 cd/m 2 , the applied voltage is 3.9 V (0.919 mA/cm 2 ) and a luminance of 58697 cd/m 2 is obtained at 10.3 V (926.9 mA/cm 2 ), higher than the previous WOLEDs with n-type ILs 19 20 . Since it is still a challenge for WOLEDs to achieve low driving voltages for practical use (e.g., <3 V for onset and <4 V at 100 cd/m 2 for portable display) 29 , our device can alleviate this difficulty. Besides, the normalized EL spectrum is shown in figure 4a inset, a CIE coordinates of (0.277, 0.354) is obtained at 100 cd/m 2 , corresponding to a CRI of 73, which is the highest value in two-color (blue/red) WOLEDs with P-IL-F structures.…”

Section: Resultsmentioning

confidence: 99%

Efficient hybrid white organic light-emitting diodes with extremely long lifetime: the effect of n-type interlayer

Liu

Wang

et al. 2014

Sci Rep

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The effect of n-type interlayer in hybrid white organic light-emitting diodes (WOLEDs) has been systematically investigated by using various n-type materials. A new finding, that the triplet energy rather than electron mobility or hole-blocking ability of interlayer plays a more positive role in the performance of hybrid WOLEDs, is demonstrated. Based on the new finding, a more efficient n-type interlayer bis[2-(2-hydroxyphenyl)-pyridine] beryllium has been employed to realize a high-performance hybrid WOLED. The resulting device (without n-doping technology) exhibits low voltages (i.e., 2.8 V for 1 cd/m2, 3.9 V for 100 cd/m2) and low efficiency roll-off (i.e., 11.5 cd/A at 100 cd/m2 and 11.2 cd/A at 1000 cd/m2). At the display-relevant luminance of 100 cd/m2, a total power efficiency of 16.0 lm/W, a color rendering index of 73 and an extremely long lifetime of 12596265 h are obtained. Such superior results not only comprehensively indicate that the n-type materials are effective interlayers to develop high-performance hybrid WOLEDs but also demonstrate a significant step towards real commercialization in WOLEDs.

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“…Since it is well-known that the main reason of the efficiency roll-off in hybrid WOLED is the triplet- triplet annihilation in P-EMLs, the unbalanced charges can cause the narrow recombination zone, leading to serious efficiency roll-off [21]. In fact, since Ir-complexes often have strong hole/ electron-capture ability or hole/electron-assisted transport ability, the moderately manipulate carrier transportation in the host may facilitate the charge balance in EMLs, leading to the reduced efficiency roll-off [22]. Hence, the reason for the low efficiency roll-off can be attributed to the multifunctional P dopants.…”

Section: Resultsmentioning

confidence: 99%

Simplified hybrid white organic light-emitting diodes with efficiency/efficiency roll-off/color rendering index/color-stability trade-off

Liu

Wang

et al. 2014

Phys. Status Solidi RRL

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A high‐performance hybrid white organic light‐emitting diode (WOLED) based on a simple structure has been developed. The resulting device exhibits a maximum total current efficiency and power efficiency of 35.7 cd/A and 30.6 lm/W, respectively. Even at a high luminance of 1000 cd/m2, a current efficiency of 32.0 cd/A and a power efficiency of 19.4 lm/W are obtained, suggesting that the device exhibits a low efficiency roll‐off. Besides, the device shows excellent color‐stability during a wide range of luminance and a high color rendering index (CRI) of 83 is obtained. Moreover, the origin of the superior properties is explored comprehensively. Such achieved results demonstrate that high efficiency, low efficiency roll‐off, stable color and high CRI can be simultaneously realized in a simplified hybrid WOLEDs. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

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Low driving voltage white organic light-emitting diodes with high efficiency and low efficiency roll-off

Cited by 19 publications

References 40 publications

Regulating Charge and Exciton Distribution in High-Performance Hybrid White Organic Light-Emitting Diodes with n-Type Interlayer Switch

Regulating Charge and Exciton Distribution in High-Performance Hybrid White Organic Light-Emitting Diodes with n-Type Interlayer Switch

Efficient hybrid white organic light-emitting diodes with extremely long lifetime: the effect of n-type interlayer

Simplified hybrid white organic light-emitting diodes with efficiency/efficiency roll-off/color rendering index/color-stability trade-off

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