Over 130 lm/W All-Phosphorescent White OLEDs for Next-generation Lighting

Kato, Kazuki; Iwasaki, Toshihiko; Tsujimura, Takatoshi

doi:10.2494/photopolymer.28.335

Cited by 28 publications

(17 citation statements)

References 9 publications

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“…Aggregation‐induced red‐shifted absorption and emission of light mediated by intermetallic coupling can be used for different purposes. For instance, if a mixture of monomeric and aggregated Pt(II) complexes is employed, white light can be outcoupled even from electroluminescent devices ,,. In “breathing” aggregates, Pt−Pt interactions can be used to sense diverse analytes .…”

Section: Introductionmentioning

confidence: 99%

Fluorination‐controlled Aggregation and Intermolecular Interactions in Pt(II) Complexes with Tetradentate Luminophores

Wilde

Gonzalez-Abradelo

Daniliuc

et al. 2018

Israel Journal of Chemistry

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In this work we describe the synthesis and DFT‐supported photophysical characterization of a series of Pt(II) complexes bearing tetradentate luminophores with increasing degree of fluorination. Aggregation into crystalline phases leads to substitution‐dependent arrangements that in all cases hinder intermetallic coupling, as intermolecular interactions are dominated by hydrogen bonding and π‐stacking. In amorphous matrices, on the other hand, we observed that an increasing level of fluorination favors the tendency towards Pt−Pt interaction upon aggregation, leading to a red‐shifted phosphorescence, if compared with monomeric species in dilute solutions and crystalline solids.

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Section: Introductionmentioning

confidence: 99%

Fluorination‐controlled Aggregation and Intermolecular Interactions in Pt(II) Complexes with Tetradentate Luminophores

Wilde

Gonzalez-Abradelo

Daniliuc

et al. 2018

Israel Journal of Chemistry

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“…The WOLED II without and with the VaNHA showed the maximum EQEs of 20.5% and 44.3%, respectively. The efficiency is the highest among reported WOLEDs without external light extraction structures except the devices with corrugated substrates as shown in Table 2 where the performances of highly efficient WOLEDs reported in literature over or close to 100 lm W −1 are summarized . The EQE of the WOLED II w/o the VaNHA is lower than WOLED I w/o VaNHA because the device is not optimized for the maximum air mode but optimized for large extractable mode.…”

Section: Performance Of Woleds II W/o and W/ Vanha And Half‐sphericalmentioning

confidence: 96%

High‐Quality White OLEDs with Comparable Efficiencies to LEDs

Jeon

Lee

Han

et al. 2018

Advanced Optical Materials

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high luminous efficacy (LE) overcoming LEDs at high luminance are believed to be a distant goal at present even with large advances in light extraction during the last couple of decades. Those advances include scatter, [1][2][3][4][5][6][7][8][9] low refractive index layer, [10] micro lens array, [11][12][13][14] photonic crystal, [15][16][17][18] low/high refractive index grid, [19][20][21] high refractive index substrate, [9,22,23,27] corrugated structure, [24][25][26][27][28][29][30][31][32] graded index, [33] randomly distributed pillar array, [34,35] biomimetic structure, [36,37] plasmonic nanocavity, [38] and so on. Among the proposed methods, the insertion of extraction medium between the glass and the indium tin oxide (ITO) electrode is regarded to have potential for further efficiency enhancement by extracting the waveguide mode in combination with the extraction method at the glass-air interface. However, despite the efficiency improvement due to the extraction layer, many of these methods often have limitations such as diffraction pattern and color distortion to be applied to general illumination systems and high-performance electronic devices. [15][16][17][18][24][25][26][27][28][29][30][31] To solve these problems such as the angular dependence and diffraction pattern, a random pattern is introduced, but the currently reported random patterns are obtained by using spontaneous methods which have difficulty in quantitative control of randomness and poor reproducibility. [34,35] It would also be recommended that the internal extraction structure does not distort the planar structure in OLEDs to prevent the potential degradation issue coming from the rough structure because active layers of OLEDs are very thin.Here, we report novel WOLEDs approaching the theoretical limit by using the highly effective extraction layer based on a randomly dispersed vacuum nanohole array (VaNHA). The random VaNHA pattern was designed with random number generation function in the unit cell of 10 × 10 µm 2 to show no specific symmetry in the reciprocal space. The random VaNHA WOLEDs in combination with a half-spherical lens exhibited comparable performance with LED lighting with unprecedentedly high LE of 164 lm W −1 , originating from high maximum external quantum efficiency (EQE) of 78% and low efficiency roll-off. In addition, the WOLEDs showed uniform emission of high-quality light with high correlated color temperature (CCT) of 3400 K, high color rendering index (CRI) around 80, no color variation with viewing angle. The light extraction structure does not have any additional detrimental effect on the device The solid-state lighting sources require high efficiency and high-quality illumination at the same time. Here, highly efficient white organic light emitting diodes (WOLEDs) comparable to LEDs are demonstrated using a random vacuum nanohole array and a half-spherical lens as internal and external light extraction layers, respectively, exhibiting the maximum external quantum efficiency of 78% and luminous efficacy of...

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“…Konica Minolta reported OLED lighting equipped with phosphorescent blue. Although it shows CCT and operational lifetime were a bit lower such as 2857K and T50 > 65,000 hr, respectively, its efficacy was record-high, close to 140 lm/W [4]. Thus, it is obvious that highly efficient blue will boost up the performance of WOLED.…”

Section: Introductionmentioning

confidence: 99%

33‐1: Invited Paper: TADF based OLED Devices

Yang

Seo

Hong

et al. 2019

Symp Digest of Tech Papers

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Although TADF has drawn a lot of attention for future high performance OLED, there has rarely been reports on the practical application. Furthermore, many researchers cast a doubt upon device lifetime. In this work, we demonstrated the applicability of TADF into OLED lighting panel. When TADF Blue was employed for 3‐stacked OLED lighting, white OLED (WOLED) showed improvement of power efficiency by about 40%. On the other hand, TADF Green in 2‐stakced WOLED reached the 70% of the device lifetime, compared with WOLED with phosphorescent green.

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Over 130 lm/W All-Phosphorescent White OLEDs for Next-generation Lighting

Cited by 28 publications

References 9 publications

Fluorination‐controlled Aggregation and Intermolecular Interactions in Pt(II) Complexes with Tetradentate Luminophores

Fluorination‐controlled Aggregation and Intermolecular Interactions in Pt(II) Complexes with Tetradentate Luminophores

High‐Quality White OLEDs with Comparable Efficiencies to LEDs

33‐1: Invited Paper: TADF based OLED Devices

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