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Polymers 2019, 11(1), 120;

PEG-assisted Sol-gel Synthesis of Compact Nickel Oxide Hole-Selective Layer with Modified Interfacial Properties for Organic Solar Cells

School of Chemical Engineering, Sungkyunkwan University (SKKU), Seobu-ro 2066, Jangan-gu, Suwon 16419, Korea
Received: 24 December 2018 / Revised: 7 January 2019 / Accepted: 9 January 2019 / Published: 11 January 2019
(This article belongs to the Special Issue Polymer-Based Solar Cells)
PDF [2310 KB, uploaded 22 January 2019]


As a p-type metal oxide, nickel oxide (NiO) has been extensively utilized for providing a favorable hole transport pathway in organic solar cells (OSCs). To obtain higher crystallinity, a post-annealing process at high temperature is required for the NiO layer. Therefore, fluorine-doped tin oxide (FTO) glass has been widely used for the substrate of NiO. However, the rough surface of the FTO substrate deteriorates the interfacial properties of the NiO layer, which hinders efficient charge extraction in OSCs. In this study, a facile polyethylene glycol (PEG)-assisted sol-gel synthesis of the compact NiO layer as the hole-selective layer is demonstrated. The compact NiO layer has a significantly uniform and smooth surface morphology, facilitating better interfacial properties for favorable charge transport. The modified interfacial properties outstandingly promote the charge migration and recombination blocking in OSCs. In addition, a hybrid structure with compact NiO and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is designed to form a cascade charge extraction and passivate possible pinholes on the NiO layer. Consequently, the compact NiO layer enhances all the parameters determining the power conversion efficiency, including the open-circuit potential (Voc), short-circuit current density (Jsc), and fill factor (FF). View Full-Text
Keywords: NiO; charge transport; ITO-free; bulk-heterojunction; organic photovoltaics NiO; charge transport; ITO-free; bulk-heterojunction; organic photovoltaics

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Kim, J.K. PEG-assisted Sol-gel Synthesis of Compact Nickel Oxide Hole-Selective Layer with Modified Interfacial Properties for Organic Solar Cells. Polymers 2019, 11, 120.

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