Journal Pre-proof Highly efficient inkjet printed flexible organic light-emitting diodes with hybrid hole injection layer Chen Feng, Xiaojing Zheng, Rui Xu, Yuangui Zhou, Hailong Hu, Tailiang Guo, Junqiao Ding, Lei Ying, Fushan Li PII: S1566-1199(20)30208-1 DOI: https://doi.org/10.1016/j.orgel.2020.105822 Reference: ORGELE 105822 To appear in: Organic Electronics Received Date: 13 April 2020 Revised Date: 20 May 2020 Accepted Date: 21 May 2020 Please cite this article as: C. Feng, X. Zheng, R. Xu, Y. Zhou, H. Hu, T. Guo, J. Ding, L. Ying, F. Li, Highly efficient inkjet printed flexible organic light-emitting diodes with hybrid hole injection layer, Organic Electronics (2020), doi: https://doi.org/10.1016/j.orgel.2020.105822. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Published by Elsevier B.V.