Electronic structures of organic materials and their interfaces studied by UV photoemission under very small light irradiation

微弱光照射下紫外光电子研究有机材料电子结构及其界面

• 批准号: 13640576
• 负责人: ISHII Hisao
• 金额: $ 2.05万
• 依托单位: Tohoku University (2002)Nagoya University (2001)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640576/
• 关键词: UV photoemission; sexiphenyl; organic semiconductor; Photoelectron Yield Spectroscopy; picoammeter; charging; carrier trap; ambient gas effect; 有機材料; 光電子分光; 試料帯電; イオン化エネルギー; 有機; 金属界面; 金

The detection sensitivity of UV photoemission is improved by using sensitive sub-pico ampere meter, which reduces the amount of photoelectrons emitted from sample substrate. This advantage is suited to investigate organic materials and interfaces since their conductivity is quite low and tends to make UPS measurements difficult due to sample charging. By using this technique, we investigated the electronic structure of Au/sexiphenyl(6P) interface. We found that Au cluster is formed at this interface and can work as carrier trap to leading anomalous spectral shift of UPS. Similar phenomenon probably related to interfaces charging was also found for fullerene / phthalocyanine interface which is a typical p-n junction.By using very low current measurements technique developed in the above study, we constructed measurement system of photoelectron yield spectroscopy (PYS) which is available in both ambient atmosphere and vacuum. Instead of a special ion counter used in previous works, sub-pico ammeter was used in this study with a specially-designed electrode. Signal-to-noise ration is also much improved due to wide dynamic range of the ammeter. The measurements of ionization potential of several organic semiconductors were successfully demonstrated. This technique is quite suited to investigate the properties of organic materials in atmosphere condition to discuss organic devices.

采用灵敏的亚皮安计提高了紫外光电子发射的检测灵敏度，减少了样品基底发射的光电子量。这一优点适合研究有机材料和界面，因为它们的电导率相当低，并且由于样品充电而往往使 UPS 测量变得困难。通过使用该技术，我们研究了Au/六苯基(6P)界面的电子结构。我们发现Au团簇在该界面形成，并且可以作为载流子陷阱导致UPS的异常光谱偏移。富勒烯/酞菁界面是典型的p-n结，也发现了类似的可能与界面充电有关的现象。通过使用上述研究中开发的极低电流测量技术，我们构建了光电子产率光谱（PYS）测量系统，该系统可用于环境大气和真空。本研究中使用亚皮安计和专门设计的电极，而不是以前的工作中使用的特殊离子计数器。由于电流表的宽动态范围，信噪比也大大提高。成功演示了几种有机半导体电离势的测量。该技术非常适合研究大气条件下有机材料的性能，以讨论有机器件。

项目成果

K.Seki: "Electronic Structure of Organic/Metal Interfaces"Thin Solid Films. 393. 298-303 (2001)

K.Seki：“有机/金属界面的电子结构”固体薄膜。

H.Ishii: "Charging and Polarization Phenomena in Thin Films and Interfaces of Organic Electronics Devices"Journal of the Institute of Electrostatics Japan. 27. 79-84 (2003)

H.Ishii：“有机电子器件薄膜和界面中的充电和极化现象”日本静电研究所杂志。