Deep-blue phosphorescent organic light-emitting diode with external quantum efficiency over 30% using novel Ir complex

Hideko Inoue; Yui Yamada; Nobuharu Ohsawa; Satoshi Seo; Shunsuke Hosoumi; Takeyoshi Watabe; Satomi Mitsumori; Hiromitsu Kido

doi:10.1117/12.2237528

23 September 2016 Deep-blue phosphorescent organic light-emitting diode with external quantum efficiency over 30% using novel Ir complex

Hideko Inoue, Yui Yamada, Nobuharu Ohsawa, Satoshi Seo, Shunsuke Hosoumi, Takeyoshi Watabe, Satomi Mitsumori, Hiromitsu Kido

Author Affiliations +

Proceedings Volume 9941, Organic Light Emitting Materials and Devices XX; 994127 (2016) https://doi.org/10.1117/12.2237528
Event: SPIE Organic Photonics + Electronics, 2016, San Diego, California, United States

Abstract

We report a newly developed deep-blue phosphorescent iridium complex exhibiting a narrow emission spectrum. The use of this complex resulted in a deep-blue organic light-emitting diode (OLED) with an external quantum efficiency (EQE) exceeding 30%. Two iridium complexes with a 4H-1,2,4-triazole ligand which has an adamantyl group at the 4-position were synthesized, with the resulting effects of the adamantyl group on photoluminescence (PL) behavior investigated. [Ir(Adm1)₃] having a 1-adamantyl group did not exhibit any emissions at room temperature, whereas [Ir(Adm2)₃] having a 2-adamantyl group exhibited a blue emission with a peak wavelength of 459 nm and a high PL quantum yield of 0.94. Structural transformations between the ground state and excited state were estimated by molecular orbital calculations, which suggests that [Ir(Adm1)₃] undergoes a considerably more extensive change than [Ir(Adm2)₃]. It is therefore probable that [Ir(Adm1)₃] ultimately experiences thermal deactivation owing to structural relaxation. Furthermore, an OLED was fabricated using [Ir(Adm2)₃] as a dopant. The associated electroluminescence spectrum had an emission peak at 457 nm and a relatively small shoulder peak at 485 nm, which are consistent with the PL spectrum. A narrowed emission spectrum with a full width at half maximum of 58 nm was obtained, leading to a deep-blue emission with high color purity (CIE, x = 0.15, y = 0.22). This device ultimately exhibited an extremely high EQE of 32% at 2 mA/cm², which was likely attributable to an increase in outcoupling efficiency via molecular orientation.

Citation Download Citation

Hideko Inoue, Yui Yamada, Nobuharu Ohsawa, Satoshi Seo, Shunsuke Hosoumi, Takeyoshi Watabe, Satomi Mitsumori, and Hiromitsu Kido "Deep-blue phosphorescent organic light-emitting diode with external quantum efficiency over 30% using novel Ir complex", Proc. SPIE 9941, Organic Light Emitting Materials and Devices XX, 994127 (23 September 2016); https://doi.org/10.1117/12.2237528

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available