Mechanisms and Applications of Spontaneous Orientation Polarization Phenomena in Amorphous Organic Thin Films

2023 Fiscal Year Final Research Report

• Project/Area Number: 20H02810
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 35030:Organic functional materials-related
• Research Institution: Chiba University
• Principal Investigator: Ishii Hisao 千葉大学, 先進科学センター, 教授 (60232237)
• Co-Investigator(Kenkyū-buntansha): 田中 有弥 群馬大学, 大学院理工学府, 准教授 (90780065)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 有機EL素子 / 巨大表面電位 / 自発配向分極 / 回転型ケルビン法 / 間欠蒸着

Outline of Final Research Achievements

In organic light emitting diodes (OLEDs), it is known that simply forming a film causes molecular orientation and polarization in the film, which greatly affects the characteristics of the device. In this study, we have searched for the factors that cause the GSP by measuring various molecules with a rotating Kelvin method, which can simultaneously measure the surface potential of the film while depositing the film. We also found that the polarization changes with time when the film depositing process is paused and a waiting period is introduced. Using this phenomenon, we also found that the polarization can be controlled by changing the waiting time. This technique can be used to further improve the performance of OLED devices.

Free Research Field

有機半導体

Academic Significance and Societal Importance of the Research Achievements

スマートフォンや大型テレビなどに導入されている有機EL素子を更に長寿命、高効率化するには、素子の膜内に発生する電荷の偏りを制御する必要がる。本研究では、製膜に一時停止プロセスを導入することで、電荷の偏りを増減したり、キャンセルしたり、プラスマイナスを入れ替えるなどの処理ができることを明らかにした。この技術は、すぐにでも応用できるものであり、有機El素子を更に高性能化することで、現在のIT社会に貢献するものである。