Plasma modification of poly(2-heptadecyl-4-vinylthieno[3,4-d]thiazole) low bandgap polymer and its application in solar cells.
For the first time, we here propose a green methodology to modify a low bandgap polymer for highly efficient solar cells using atmospheric pressure plasma jet or soft plasma operating on different feeding gases (air, Ar and N2). The physical properties of the modified polymer were investigated using conductivity measurements, UV-visible spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammograms, atomic force microscopy, cathodoluminescence and confocal Raman spectroscopy. Further, we examined the variation of the work function of the polymer before and after plasma treatment using a γ-focused ion beam. Additionally, photovoltaic cells based on the plasma-modified polymer having ITO/PEDOT:PSS/PHVTT (with or without plasma modification):PC71BM/LiF/Al configuration were fabricated and then characterized. We found that the power conversion efficiency (PCE) of the plasma-modified polymer increased dramatically as compared to the control polymer (without plasma treatment). PCE of the control polymer was found to be 4.11%, while after air, Ar and N2 gas plasma treatment the polymer showed PCEs of 4.85%, 4.87% and 5.14% respectively. Thus, plasma treatment not only alters the surface properties, but also modifies the bulk properties (changes in HOMO and LUMO bandgap level). Hence, this work provides new dimensions to explore more about plasma and polymer chemistry.
Plasma BioScience Research Center/Department of Electrophysics, Kwangwoon University, Seoul, Korea 139-701. ehchoi@kw.ac.kr.
Pankaj
P
Attri
Vishal
V
Bharti
Young Sun
YS
Kim
Jitender
J
Gaur
Suresh
S
Chand
Gi-Chung
GC
Kwon
Seung-Hyun
SH
Lee
Weontae
W
Lee
Eun Ha
EH
Choi
In Tae
IT
Kim
D011211:Electric Power Supplies; D004867:Equipment Design; D055772:Green Chemistry Technology; D058626:Plasma Gases / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012993:Solar Energy; D013844:Thiazoles / Q000737:chemistry*
D058626:Plasma Gases; D011108:Polymers; D013844:Thiazoles