Journal
ACS APPLIED MATERIALS & INTERFACES
Volume 9, Issue 8, Pages 7834-7842Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acsami.6b16341
Keywords
light soaking; interfacial modification; PEDOT:PSS/ZnO; flexible inverted organic solar cells; work function regulation
Funding
- National Natural Science Foundation of China [61306073]
- Ministry of Science and Technology of China [2016YFA0200700]
- Jiangsu Provincial Natural Science Foundation [BK20130346, BE2015071]
- Strategic Priority Research Program of the Chinese Academy of Sciences [XDA09020201]
Ask authors/readers for more resources
Silver nanogrid based flexible transparent electrode is recognized as the most promising alternative to ITO electrode for organic electronics, owing to its low production cost and excellent flexibility. Typically, a highly conductive thin film coating layer, such as highly conductive PEDOT:PSS (HC-PEDOT:PSS) is usually deposited onto the Ag-grid electrode to smooth the surface and to minimize the sheet resistance. In this paper, we found that inverted flexible polymer solar cells with structure of Ag-grid/HC-PEDOT:PSS/ZnO/photoactive layer/MoO3/Al generally exhibits strong S-shaped J-V curves, which could be eliminated by light-soaking treatment. Kelvin probe force microscope (KPFM) measurement proved that a large work function (WF) difference (0.70 eV) between HC-PEDOT:PSS and ZnO is the main reason for the formation of S-shape. White light soaking of the Ag-grid/HC-PEDOT:PSS gradually decreased the WF of HC-PEDOT:PSS from 5.10 to 4.60 eV, leading to a reduced WF difference between HC-PEDOT:PSS and ZnO from 0.70 to 0.38 eV. Such a WF difference decrease was believed to be the working mechanism for the light-soaking effect in this flexible device. Based on this finding, the HC-PEDOT:PSS solution was then modified by doping with polyethylenimine (PEI) and aqueous ammonia. The modified PEDOT:PSS film is characteristic of adjusting WF through varying PEI doping concentrations. By using such a modified PEDOT:PSS layer, light soaking-free flexible inverted polymer solar cell with a power conversion efficiency of 6.58% was achieved for PTB7-Th:PC71BM cells. The current work provides a useful guideline for interfacial modification for Ag-grid based flexible electrode.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available