Light-emitting Organic Photovoltaic Devices Based on Rubrene/PTCDI-C13 Stack

Yamada, Masahiro; Naka, Shigeki; Okada, Hiroyuki

doi:10.5796/electrochemistry.85.280

Cited by 12 publications

(7 citation statements)

References 18 publications

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“…5 According to these reasons, the operating voltage of OLED emitting about 600 nm light at 100 cd/m 2 , which is a general display driving condition, is very high as 4.5 V. 6 One of the possible strategies to reduce the operating voltage of OLED is utilizing upconversion (UC) emission based on triplet-triplet annihilation (TTA) sensitized by a charge transfer (CT) state at the donor/acceptor (D/A) interface. [7][8][9][10][11][12] The active layer of UC-OLED consists of two: emitter (donor) layer playing hole transport and emission, and acceptor layer for electron transport. The operating mechanism involved in UC-OLED are as illustrated in Figure 1a: at first, injected charge formed both singlet and triplet CT state, denoted as CT1 and CT3, at the D/A interface.…”

Section: Main Textmentioning

confidence: 99%

Efficient Interfacial Upconversion Enabling Bright Emission with Extremely Low Driving Voltage in Organic Light-Emitting Diodes

Izawa

Morimoto²,

Naka³

et al. 2021

Preprint

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Reducing operating voltage is the remaining frontier for organic light-emitting diodes (OLEDs) because their quantum efficiency (QE) of electroluminescence has been already maximized. Herein, we report an efficient OLED in which a blight emission equivalent to a luminance of a display is achieved by only a 1.5 V battery. The OLED is based on upconversion (UC) emission utilizing triplet-triplet annihilation occurring near donor/acceptor (D/A) interface. We found that a character of a charge transfer state that is key intermediate for the UC emission could be controlled by D/A interfacial interaction. As a result, parasitic loss processes for UC were greatly suppressed from over 90% to about 10%, and two order of magnitude higher QE than the previous UC-OLED was achieved. Our result demonstrated that the efficient UC could be realized by the management of the energy transfer steps at the D/A interface and utilizing UC emission can be one of the possible candidate for efficient OLED with extremely low driving voltage.

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Section: Main Textmentioning

confidence: 99%

Efficient Interfacial Upconversion Enabling Bright Emission with Extremely Low Driving Voltage in Organic Light-Emitting Diodes

Izawa

Morimoto²,

Naka³

et al. 2021

Preprint

Self Cite

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“…The TTA-UC emission sensitized by the CT state has been mainly studied with rubrene, which shows yellow emission in previous studies. [9][10][11][12][13] From our experience, we obtained efficient blue TTA-UC emission by determining an appropriate combination of blue emitter (donor) and acceptor (electron transport) from 21 organic molecules. According to this design concept, the turn-on voltage of the blue OLED is greatly reduced to as low as 1.47 V, and the OLED reaches 100 cd/m 2 , which is equivalent to the luminance of a typical display, at 1.97 V. Furthermore, the blue emission in the UC-OLED originated from a stable low energy T1 and subsequent fast TTA-UC emission, 14 which could potentially avoid degrading the constituent materials.…”

Section: Introductionmentioning

confidence: 99%

Blue Organic Light-Emitting Diode with a Turn-on Voltage at 1.47 V

Izawa

Morimoto

Fujimoto

et al. 2023

Preprint

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Among the three primary colors, blue emission in organic light-emitting diodes (OLEDs) are highly important but very difficult to develop. OLEDs have already been commercialized; however, blue OLEDs have the problem of requiring a high applied voltage due to the high-energy of blue emission. Herein, an ultralow voltage turn-on at 1.47 V for blue emission with a peak wavelength at 462 nm (2.68 eV) is demonstrated in an OLED device. This OLED reaches 100 cd/m2, which is equivalent to the luminance of a typical commercial display, at 1.97 V. Blue emission from the OLED is achieved by the selective excitation of the low-energy triplet states at a low applied voltage by using the charge transfer (CT) state as a precursor and the triplet-triplet annihilation, which forms one emissive singlet from two triplet excitons. We found that the essential component for efficient blue emission is a smaller energy difference between the CT state and triplet exciton, accelerating the energy transfer between the two states and achieving the optimal performance by avoiding direct decay from the CT state to the ground state. Our study demonstrates that the developed OLED allows for a much longer operation lifetime than that from a typical blue phosphorescent OLED because the blue emission originates from a stable low-energy triplet exciton that avoids degrading the constituent materials.

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“…Recently, the organic semiconductors have attracted enormous attentions due to their great potential applications in optoelectronic devices, organic light-emitting diodes (OLEDs), organic eld-effect transistors (OFETs), organic transistors and organic solar cells (OSCs) [1][2][3][4][5]. Furthermore, the Rubrene with formula (C 42 H 28 , 5, 6, 11, 12 -tetraphenylnaphtacene) is one of the most researched organic semiconductor materials for their remarkable charge carry mobility and luminous e ciency [6-10].…”

Section: Introductionmentioning

confidence: 99%