Electrochemical Spectroscopic Methods for the Fine Band Gap Electronic Structure Mapping in Organic Semiconductors

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• 作者：Katar铆na Gmucov谩 ; Vojtech N谩da啪dy ; Franti拧ek Schauer ; Michal Kaiser ; Eva Majkov谩
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：July 16, 2015
• 年：2015
• 卷：119
• 期：28
• 页码：15926-15934
• 全文大小：367K
• ISSN：1932-7455

文摘

Functionality of organic photonic devices is markedly influenced by the electronic band structure of the used materials. An easy and quick determination of the density of states function (DOS) in the whole energy range from HOMO to LUMO, including the presence of defect states in the band gap, is a prerequisite to a successful design of photonic devices. In this study we present the fine band gap electronic structure mapping in P3HT with two electrochemical spectroscopic methods: the energy-resolved electrochemical impedance spectroscopy (ER-EIS) and the kinetic sensitive voltcoulometry (VCM). We showed that the P3HT exposition to air results in the change of light-induced polaron states in the band gap. The electrochemically measured data are compared with those from the literature, obtained with combined optical spectroscopic methods, electrical methods, or first-principles calculations. The ER-EIS method has been shown as capable of providing valuable information on the DOS in the whole energy range from HOMO to LUMO, and the VCM method opens the possibility to study separately the charge transfer (redox) processes with different kinetics.