Multiple-Trapping Governed Electron Transport and Charge Separation in ZnO/In2S3 Core/Shell Nanorod Heterojunctions

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• 作者：Christian Strothk盲mper ; Klaus Schwarzburg ; Robert Sch眉tz ; Rainer Eichberger ; Andreas Bartelt
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：January 12, 2012
• 年：2012
• 卷：116
• 期：1
• 页码：1165-1173
• 全文大小：467K
• 年卷期：v.116,no.1(January 12, 2012)
• ISSN：1932-7455

文摘

Solar cells based on ZnO nanorods with thin In₂S₃ shells have recently shown promising solar conversion efficiencies. Using optical-pump terahertz-probe (OPTP) spectroscopy, the charge separation across ZnO/In₂S₃ interfaces is analyzed for ZnO nanorods with systematically varied In₂S₃ absorber thicknesses, measuring transient photoconductivities with subpicosecond time resolution. Whereas for neat In₂S₃ films the photoconductivity is dominated by fast multiple trapping and second order recombination, the ZnO/In₂S₃ heterostructures exhibit slow electron injection dynamics occurring within hundreds of picoseconds, and long-lived charge-separated states. The transient photoconductivity of the ZnO/In₂S₃ core/shell system is analyzed with a correlated three component effective medium approach, yielding a significant decrease of the charge separation efficiency with increasing shell thickness.