title: Switching Hole and Electron Transports of Molecules on Metal Oxides by Energy Level Alignment Tuning.
abstract: Charge transport at organic/inorganic hybrid contacts significantly affects the performance of organic optoelectronic devices because the unfavorable energy level offsets at these interfaces can hinder charge injection or extraction due to large barrier heights. Herein, we report a technologically relevant method to functionalize a traditional hole-transport layer of solution-processed nickel oxide (NiOx) with various interlayers. The photoemission spectroscopy measurements reveal the continuous tuning of the NiOx substrate work function ranging from 2.5 to 6.6 eV, enabling the alignment transition of energy levels between the Schottky-Mott limit and Fermi level pinning at the organic/composite NiOx interface. As a result, switching hole and electron transport for the active organic material on the composite NiOx layer is achieved due to the controlled carrier injection/extraction barriers. The experimental findings indicate that tuning the work function of metal oxides with optimum energy level offsets can facilitate the charge transport at organic/electrode contacts.
authors: Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , Suzhou 215123, China.
authors: Zhong-Min
authors: ZM
authors: Bao
authors: Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , Suzhou 215123, China.
authors: Rui-Peng
authors: RP
authors: Xu
authors: Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , Suzhou 215123, China.
authors: Chi
authors: C
authors: Li
authors: Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , Suzhou 215123, China.
authors: Zhong-Zhi
authors: ZZ
authors: Xie
authors: Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , Suzhou 215123, China.
authors: Xin-Dong
authors: XD
authors: Zhao
authors: Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , Suzhou 215123, China.
authors: Yi-Bo
authors: YB
authors: Zhang
authors: Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , Suzhou 215123, China.
authors: Yan-Qing
authors: YQ
authors: Li
authors: Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , Suzhou 215123, China.
authors: Jian-Xin
authors: JX
authors: Tang
keywords: energy level alignment; hybrid inorganic/organic interface; injection barrier tuning; organic optoelectronics; photoemission spectroscopy