Determination of charge injection barriers in organic semiconductors

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K05064
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 32020:Functional solid state chemistry-related
• Research Institution: University of Hyogo
• Principal Investigator: Tajima Hiroyuki 兵庫県立大学, 理学研究科, 教授 (60207032)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 蓄積電荷測定法 / 電荷注入障壁 / ACM / 有機デバイス / 有機FET / フタロシアニン / ペンタセン

Outline of Final Research Achievements

Accumulated charge measurement (ACM) is an experimental technique for studying the charge injection and extraction process in the MIOM junction comprising metal electrode 1(M1), insulator(Ins), organic semiconductor(OS), metal electrode 2(M2). This technique was reported by the author for the first time in 2016. The aim of this project is to develop this technique based on experimental and theoretical studies.
In this project, the author clarified that there are two types of charge extraction processes in the MIOM junctions. In the thermal equilibrium (TE) process, charge evacuation simultaneously occurs at the Ins/OS and OS/M2 boundaries. On the other hand, in the non-thermal equilibrium (NTE) process, charge evacuation at the OS/M2 boundary occurs in the first step, followed by charge evacuation at the Ins/OS boundary in the second step. To evaluate the injection barrier at the OS/M2 interface based on ACM, NTE process is more convenient than TE process.

Free Research Field

有機電子物性

Academic Significance and Societal Importance of the Research Achievements

有機薄膜デバイス作成においては、金属／有機半導体あるいは絶縁体／有機半導体等、種々の界面の物性を理解する必要がある。しかしながら、このような実験を系統的に行う実験手法は、光電子分光測定等、分光学的手法に限定されており、実デバイスを用いた実験手法は報告されていなかった。本研究は実デバイスを用いた新しい実験手法の開発に関連するものであり、今後の有機薄膜デバイス作成に大きな影響を与えることが期待される。