| 概 要 |
Abstract: Electric double layers (EDLs) have been extensively studied in electrochemistry, as they enable large charge accumulation at electrode interfaces. In recent years, EDLs have attracted much attention for application in electronic devices, such as supercapacitors, field effect transistors, etc. In this presentation, we report on their application to optoelectronic conversion and energy storage.
Organic optoelectronic conversion for optical communication. Transient photocurrents from organic optoelectronic devices have previously been regarded as an extrinsic property. However, we have recently investigated its application to effective, ultrafast optoelectronic conversion. A cell architecture, [Electrode 1 | Charge Separation Layer (CSL) | Polarization Layer (PL) | Electrode 2], was specially designed to produce a large transient photocurrent, where a thick PL effects an enhanced charge separation in a thin CSL [1]. By examining various combinations of materials for the CSL and PL, we found that the transient current was significantly enhanced with an increase in the dielectric constant of the PL [1]. Especially, the photocells with ionic-liquid PLs produced much larger transient currents than those with solid-state PLs, probably due to formation of EDLs in ionic liquids [2]. We also demonstrated an optoelectric conversion for NIR light at frequencies up to 10 MHz [3].
Rechargable molecular cluster batteries. High-capacity energy storage is the key to achieving a sustainable society. Recently, we proposed rechargeable molecular cluster batteries (MCBs), in which the anode is Li metal and the cathode includes a transition metal cluster complex, such as Mn12, POMs, etc. [4]. These MCBs were found to operate with large battery capacities. Furthermore, nano-hybridization between these transition metal cluster complexes and carbon nanotubes significantly enhanced the battery capacities and stability [5]. In-operando XAFS [6] and NMR measurements indicated that these large capacities can be understood as a combination of the redox change of the metal ions and a supercapacitor effect at the electrode surface.
[1] L. Hu, et al. Appl. Phys. Lett. 96, 243303 (2010).
[2] B. Li, et al. Appl. Phys. Lett. 100, 163304 (2012).
[3] S. Dalgleish, et al., J. Am. Chem. Soc., 134, 12742 (2012).
[4] H. Yoshikawa, et al. Chem. Commun, 3169 (2007).
[5] N. Kawasaki, Angew. Chem. Int. Ed., 50, 3471 (2011).
[6] H. Yoshikawa, et al. Inorg. Chem., 48, 9057 (2009).
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