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International Journal of Photoenergy
Volume 2016 (2016), Article ID 3675036, 7 pages
http://dx.doi.org/10.1155/2016/3675036
Research Article

Stable Inverted Low-Bandgap Polymer Solar Cells with Aqueous Solution Processed Low-Temperature ZnO Buffer Layers

1State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, School of Microelectronics, Xidian University, 2 South Taibai Road, Xi’an 710071, China
2Huanghe Hydropower Solar Industry Technology Co., Ltd., 369 South Yanta Road, Xi’an 710061, China
3Guilin University of Electronic Technology, No. 1 Jinji Road, Guilin 541004, China

Received 6 May 2016; Revised 21 August 2016; Accepted 24 August 2016

Academic Editor: Hongxia Wang

Copyright © 2016 Chunfu Zhang et al. 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.

Abstract

Efficient inverted low-bandgap polymer solar cells with an aqueous solution processed low-temperature ZnO buffer layer have been investigated. The low-bandgap material PTB-7 is employed so that more solar light can be efficiently harvested, and the aqueous solution processed ZnO electron transport buffer layer is prepared at 150°C so that it can be compatible with the roll-to-roll process. Power conversion efficiency (PCE) of the inverted device reaches 7.12%, which is near the control conventional device. More importantly, the inverted device shows a better stability, keeping more than 90% of its original PCE after being stored for 625 hours, while PCE of the conventional device is only 75% of what it was. In addition, it is found that the ZnO thin film annealed in N2 can obviously increase PCE of the inverted device further to 7.26%.