Carrier Transport in Zinc Phthalocyanine Doped with a Fluorinated Perylene Derivative: Bulk Conductivity versus Interfacial Injection

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• 作者：Lin Chen ; Ligong Yang ; Zhisheng Yang ; Minmin Shi ; Mang Wang ; Hongzheng Chen ; Wenhua Zhang ; Faqiang Xu
• 刊名：Journal of Physical Chemistry C
• 出版年：2009
• 出版时间：October 1, 2009
• 年：2009
• 卷：113
• 期：39
• 页码：17160-17169
• 全文大小：429K
• 年卷期：v.113,no.39(October 1, 2009)
• ISSN：1932-7455

文摘

P-doping of zinc phthalocyanine (ZnPc) with a perylene derivative of N,N′-di-(2,4-difluorophenyl)-3,4,9,10-perylenetetracarboxylic diimide (D24DFPP) is investigated for wide range of doping ratios. I−V measurements in air for the three-layered devices [Au(40 nm)/organic(400 nm)/Au(35 nm)] show a 4 orders of magnitude increment in current density after doping. Ultraviolet and X-ray photoemission spectroscopy (XPS and UPS) studies confirm that the efficient host-to-dopant electron transfer is the primary reason for this increment. Carrier transport is found to be more efficient in the lightly doped film than in the heavily doped film for our D24DFPP-doped ZnPc system. Morphology study and the detailed modeling analysis attribute this to both bulk conductivity and interfacial injection effect. The lower injection barrier and better energy level alignment with the electrode in the lightly doped ZnPc film facilitate the field-emission tunneling process, leading to a more efficient carrier injection compared with the heavily doped film. For the heavily doped film, the inferior transporting performance is also correlated with its disrupted crystalline structure and more severe phase separation.