Effect of halogenated impurities on lifetime of organic light emitting diode

Hayato Yamawaki; Kunihiko Suzuki; Tomohiro Kubota; Takeyoshi Watabe; Ayumi Ishigaki; Rina Nakamura; Hideko Inoue; Harue Nakashima; Nozomi Horikoshi; Hiromi Nowatari; Riho Kataishi; Toshiki Hamada; Toshiki Sasaki; Tsunenori Suzuki; Satoshi Seo

doi:10.1117/12.2237544

23 September 2016 Effect of halogenated impurities on lifetime of organic light emitting diode

Hayato Yamawaki, Kunihiko Suzuki, Tomohiro Kubota, Takeyoshi Watabe, Ayumi Ishigaki, Rina Nakamura, Hideko Inoue, Harue Nakashima, Nozomi Horikoshi, Hiromi Nowatari, Riho Kataishi, Toshiki Hamada, Toshiki Sasaki, Tsunenori Suzuki, Satoshi Seo

Author Affiliations +

Proceedings Volume 9941, Organic Light Emitting Materials and Devices XX; 99410P (2016) https://doi.org/10.1117/12.2237544
Event: SPIE Organic Photonics + Electronics, 2016, San Diego, California, United States

Abstract

We investigated a correlation between lifetime and the halogen element concentration in an organic light-emitting diode (OLED) and conducted experiments and simulations to discuss degradation mechanisms due to the halogen. OELD is generally formed of high-purity materials. Since the synthesis of high-purity materials takes time and cost, quantitative understanding of the kind, amount, and influence of impurities in OLED devices is expected. The results of combustion ion chromatography show that, if the chlorine concentration in the host material is more than several parts per million, the lifetime of the device is drastically reduced. The chlorine element, which is derived from the chlorinated by-product of the host material, is found to be transferred from the chloride to other materials (e.g., an emissive dopant) according to the results of LC-MS analysis. In addition, the electron transport layer including such impurities is also found to adversely affect the lifetime. The results of TOF-SIMS analysis suggest that the dissociated chlorine element diffuse to the light-emitting layer side when the device is driven. The results of simulations (Gaussian 09) and electrochemical analyses (cyclic voltammetry and electrolysis) reveal that the halogen element is easy to dissociate from halide by excitation or reduction. The halogen element can repeat reactions with the peripheral materials by excitation or reduction and cause damages, e.g., generate radicals or further reaction products due to the radicals. The results of simulation suggest that, such compounds have low energy level and become quenchers.

Citation Download Citation

Hayato Yamawaki, Kunihiko Suzuki, Tomohiro Kubota, Takeyoshi Watabe, Ayumi Ishigaki, Rina Nakamura, Hideko Inoue, Harue Nakashima, Nozomi Horikoshi, Hiromi Nowatari, Riho Kataishi, Toshiki Hamada, Toshiki Sasaki, Tsunenori Suzuki, and Satoshi Seo "Effect of halogenated impurities on lifetime of organic light emitting diode", Proc. SPIE 9941, Organic Light Emitting Materials and Devices XX, 99410P (23 September 2016); https://doi.org/10.1117/12.2237544

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