Synchrotron induced photoelectron spectroscopy on drop casted donor/acceptor bulk heterojunction: Orbital energy line up in DH6T/PCBM blends

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• 作者：Julia Maibach ; Eric Mankel ; Thomas Mayer ; ^{mayerth@surface.tu-darmstadt.de} ; Wolfram Jaegermann
• 关键词：Organic semiconductor ; Electronic structure ; Bulk heterojunction ; Orbital energy line up ; Solution processed interfaces
• 刊名：Surface Science
• 出版年：2013
• 出版时间：June, 2013
• 年：2013
• 卷：612
• 期：Complete
• 页码：L9-L11
• 全文大小：465 K

文摘

High resolution synchrotron-induced photoelectron spectroscopy (SXPS) is most valuable in determining the electronic properties of semiconductors (SC) and their interfaces. Applying SXPS to organic SCs prepared from solution is hindered by the pressure gap of preparation and UHV analysis. With this letter we show that i) thin organic SC films can be prepared from solution with little enough contamination to analyze their electronic structure with highest surface sensitivity, ii) the electronic structure of solution processed organic SC interfaces can be determined using bulk heterojunction systems (BHJ), and iii) for the specific donor/acceptor system ¦Á,¦Ø-Dihexylsexithiophene (DH6T)/Phenyl-C61-butyric acid methyl ester (PCBM) the HOMO line up changes from 0.94 eV of the pristine materials comparing their ionization energies to 0.69 eV in the BHJ blend, indicating the formation of interface dipole potentials. In addition, disproportionate spectral intensities indicate DH6T surface enrichment in the blend.