Influence of vacuum chamber impurities on the lifetime of organic light-emitting diodes

Hiroshi Fujimoto, Takashi Suekane, Katsuya Imanishi, Satoshi Yukiwaki, Hong Wei, Kaori Nagayoshi, Masayuki Yahiro, Chihaya Adachi

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

We evaluated the influence of impurities in the vacuum chamber used for the fabrication of organic light-emitting diodes on the lifetime of the fabricated devices and found a correlation between lifetime and the device fabrication time. The contact angle of the ITO substrates stored the chamber under vacuum were used to evaluate chamber cleanliness. Liquid chromatography-mass spectrometry was performed on Si wafers stored in the vacuum chamber before device fabrication to examine the impurities in the chamber. Surprisingly, despite the chamber and evaporation sources being at room temperature, a variety of materials were detected, including previously deposited materials and plasticizers from the vacuum chamber components. We show that the impurities, and not differences in water content, in the chamber were the source of lifetime variations even when the duration of exposure to impurities only varied before and after deposition of the emitter layer. These results suggest that the impurities floating in the vacuum chamber significantly impact lifetime values and reproducibility.

Original languageEnglish
Article number38482
JournalScientific reports
Volume6
DOIs
Publication statusPublished - Dec 13 2016

All Science Journal Classification (ASJC) codes

  • General

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