– 1 –

OOLLEEDD

OLED EL nminjection

exciton4

1) s=0 25%s=1 75%

100 75

OLED1950

OLED2) 1997 1

triplet-triplet annihilation : TTA OLED

OLED1950 1990

3,4) Eu 5) Tb 6)

77K1990 PtOEP7) Ir(ppy)38,9) Pt Ir

100% EL IQE 2 Ir

Ir 2t1510)

2012 3(Thermally Activated Delayed Fluorescence, TADF)

11) TADF

1930100

11)

– 2 –

TTAADDFF TADF

T1 S1 S0 3TADF TADF

T1 S1

Reverse Intersystem Crossing RISC S1 S1 S0

Radiative decay

RISC (T1 S1) T1 S0 nonradiative decay RISC kRISCT1 S0 knr' kRISC > knr'S1 S0 S1 S0 S1 S0

kr S1 S0 knr

2 kRISC > knr' kr > knr TADF

Year

Inte

rnal

EL ef

ficien

cy (%

)

1950 1960 1970 1980 1990 2000 2010 2020

100

50

75

25

0

AnthraceneSingle Crystal

p-n type

Guest-hostdoping system

Keto-CoumarinLow temp phos.

PtOEP

Ir(ppy)3

4CzIPN

PIC-TRZ

SnF2 (OEP)Double hetero

TTA

N

O

O

N

ON

Al

N

N

N

Ir

Anthracenederivatives

N NPt

N N

62.5%

1st -GFluorescence

2nd-GPhosphorescence

3rd-GTADF

11 OOLLEEDD TTAADDFFTTTTAA

– 3 –

110000

2255 7755TTAADDFF

kRISC > knr' kRISC EST

kRISC EST kRISC exp(−ΔEST)EST kRISC S1 T1

Highest Occupied Molecular Orbital, HOMO Lowest Unoccupied Molecular Orbital, LUMO 1 HOMO LUMO

EST 1EST HOMO LUMO 2 K (

EST =2K) K HOMO LUMO 1)

𝐾𝐾 = ∬𝜙𝜙%(1)𝜙𝜙)(2)+,-.𝜙𝜙%(2)𝜙𝜙)(1) 𝑑𝑑𝜏𝜏+𝑑𝑑𝜏𝜏1 （式１）

(f) f

(µ) ( 2)

𝜇𝜇 = ∬𝜙𝜙3454 |𝑒𝑒𝑒𝑒|𝜙𝜙%)54𝑑𝑑𝜏𝜏 （式２）

HOMO LUMOHOMO LUMO 11) EST

TADF HOMO LUMOS1 S0 S1 S0

HOMO LUMOEST

TADF EST kRISC EST

kRISC T S 1 µ skRISC 1)

𝑘𝑘:;<= = 𝐴𝐴exp(−DEFGHIJ

)

kRISC 2EST EST

– 4 –

A

A ≈⟨NO|3PQ|NR⟩

DEFG

HSO −(Fi) (Ff)

n-p* ATADF D-A

n-p*n-p* TADF

CT CT (1CT)CT (3CT)

3LE 312)

El-Sayed CT CTLE LE

T S CTLE Mixing CT LE 12,13) through-

space14) CT

((kkRRIISSCC)) DDEESSTT

TADF D-A

TADF2014 D-A n-p*

TADF 15) − PLQY 30250ns

charge resonance HOMOLUMO TADF 16)

27nm

Pre-factor A

DDEST

– 5 –

TADF D-An-p*

17)

75

-

18)

25 T1 S1 RISC100% TADF

19) 100%1/4

RISC ~106 s–1

TADF

– 6 –

20)

nsµs Ir TADF

1 21)

TADF OPERA ( )

Kyulux

1) N. J. Turro, “Modern Molecular Photochemistry” University Science Books, (1991). 2) M. Pope and C. E. Swenberg, “Electronic Processes in Organic Crystals and Polymers”,

(Oxford) 1999. 3) K. Honda, “Photochemical Processes in Organized Molecular Systems”, 1991 (North-Holland

Delta Series), p. 437 (1991). 4) S. Hoshino and H. Suzuki, Appl. Phys. Lett., 69, 224 (1996). 5) J. Kido, K. Nagai, and Y. Ohashi, Chem. Lett., 19, 657 (1990). 6) (1990). 7) M. A. Baldo, D. F. O'Brien, Y. You, A. Shoustikov, S. Sibley, M. E. Thompson and S. R. Forrest,

Nature, 395, 151 (1998). 8) C. Adachi, M. A. Baldo, M. E. Thompson, and S. R. Forrest, J. Appl. Phys., 90, 5048 (2001). 9) S. Lamansky, P. Djurovich, D. Murphy, F. Abdel-Razzaq, H. E. Lee, C. Adachi, P. E. Burrows,

S. R. Forrest, and M. E. Thompson, J. Am. Chem. Soc. 123, 4304 (2001). 10) Y. Zhang, J. Lee and S. R. Forrest, Nature Commun., 5, 5008 (2014). 11) H. Uoyama, K. Goushi, K. Shizu, H. Nomura, and C. Adachi, Nature, 492, 234 (2012). 12) J. Gibson, A. P. Monkman, T. J. Penfold, ChemPhysChem 17, 2956–2961 (2016). 13) T. Hosokai, H. Matsuzaki, H. Nakanotani, K. Tokumaru, T. Tsutsui, A. Furube, K. Nasu, H.

Nomura, M. Yahiro, and C. Adachi, Science Advances, 3, e1603282 (2017). 14) H. Tsujimoto, D.-G. Ha, G. Markopoulos, H. S. Chae, M. A. Baldo, and T. M. Swager, J.

Am. Chem. Soc., 139, 4894 (2017). 15) J. Li, Q. Zhang, H. Nomura, H. Miyazaki and C. Adachi, Appl. Phys. Lett., 105, 013301 (2014). 16) T. Hatakeyama, K. Shiren, K. Nakajima, S. Nomura, S. Nakatsuka, K. Kinoshita, J. Ni, Y. Ono,

and T. Ikuta, Adv. Mater., 28, 2777 (2016). 17) M. Mamada, K. Inada, T. Komino1, W. J. Potscavage, Jr., H. Nakanotani, C. Adachi, ACS

Central Science, 3, 769 (2017). 18) M. Inoue, T. Matsushima, H. Nakanotani, and C. Adachi, Chem. Phys. Lett., 624, 43 (2015). 19) H. Nakanotani, T. Furukawa, and C. Adachi, Adv. Opt. Mater., 3, 1381 (2015). 20) H. Nakanotani, T. Furukawa, T. Hosokai, T. Hatakeyama and C. Adachi, Adv. Opt. Mater.,

1700051 (2017). 21) R. Kabe and C. Adachi, Nature, 550, 384 (2017).