Tomimatsu Akihiro, Yokokura Seiya, Reissig Louisa, Dalgleish Simon, Matsushita Michio M, Awaga Kunio
Department of Chemistry & Integrated Research Consortium on Chemical Sciences (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
Phys Chem Chem Phys. 2019 Jun 26;21(25):13440-13445. doi: 10.1039/c9cp01221d.
Recently, we proposed a [metal|insulator|semiconductor|insulator|metal] (MISIM) photocell, as a novel architecture for high-speed organic photodetectors. The electric polarization in the S layer, induced by modulated light illumination, propagates into the outside circuit as a polarization current through the I layers, without any carrier transfer across the interfaces. In the present work, we examined the MISIM photocells consisting of zinc-phthalocyanine(ZnPc)-C60 bilayers for the S layer and Parylene C for the two I layers, to understand the fundamental aspects of the MISIM photocells, such as current polarity and modulation-frequency dependence. It was found that, in such devices, the current polarity was primarily determined by the polarization in the S layer, which was induced by the donor-acceptor charge-transfer upon illumination. Furthermore, the ON and OFF current, which appeared in the periods of illumination-on and -off, respectively, exhibited significantly different dependence on the modulation frequency. This was well-explained by an imbalance between a quick polarization in the S layer during illumination and its slow relaxation in the dark.
最近，我们提出了一种[金属|绝缘体|半导体|绝缘体|金属]（MISIM）光电池，作为高速有机光电探测器的一种新型架构。由调制光照射引起的S层中的电极化，作为极化电流通过I层传播到外部电路，而没有任何载流子在界面间转移。在本工作中，我们研究了由用于S层的锌酞菁（ZnPc）-C60双层和用于两个I层的聚对二甲苯C组成的MISIM光电池，以了解MISIM光电池的基本特性，如电流极性和调制频率依赖性。结果发现，在这类器件中，电流极性主要由S层中的极化决定，而S层中的极化是由光照时供体-受体电荷转移引起的。此外，分别出现在光照开启和关闭期间的通电流和断电流，对调制频率表现出显著不同的依赖性。这可以通过光照期间S层中快速极化与其在黑暗中缓慢弛豫之间的不平衡得到很好的解释。
