A Study on the Polymer/Fullerene Bulk Heterojunction Solar Cells
Date Issued
2007
Date
2007
Author(s)
Wei, Hung-Yu
DOI
zh-TW
Abstract
Solid type polymer solar cells has been hotly studied in this decade, although the efficiency is still lower than 5~6 %, its low fabrication cost and easy process make it attractive to researchers, and its flexibility is another outstanding property. It’s power conversion efficiency is low but already enough for some low power devices, such as small fans or calculators. This study is mainly discussing the effect of donor/acceptor ratio, electron transfer layer and hole transfer layer on the performances of bulk heterojunction solar cells, and suggests a process of oxidation polymerization of hole transfer layer in order to prevent the degradation of cell in the environment containing water molecules.
In the research of donor/acceptor ratio, we tried to fabricate solar cell devices with different ratio of donor and acceptor and observe the trend of cell efficiency and short circuit current change with donor/acceptor ratio, and we found that when we fix the concentration of electron donor, and increase the concentration of acceptor, the cell efficiency and short circuit current increases, at the point of donor/acceptor = 1/0.8 reaches the optimum. And if we keep on increasing the concentration of acceptor, the cell performance and short circuit current decreases gradually. In this research, we use atomic force microscope ( AFM ) to observe the morphology of thin film, and found that when acceptor increases, the phase separation in the thin film will increase, when the acceptor concentration is higher than donor/acceptor = 1/0.8, vertical phase separation will occur, and the possibility of recombination will be increased.
This research also tried to increase the conductivity of hole transfer layer by adding DMSO into PEDOS:PSS solution. We found that the conductivity will not be improved by adding DMSO into PEDOT:PSS solution, because the mixed solution cannot provide a perfect thin film. We also compare the cell performances with and without LiF electron transfer layer and found that adding LiF layer can increase the cell efficiency by increasing short circuit current and fill factor.
In this research, we did not fabricate our solar cell devices in the glove box or in the clean room, and we get 2.68 % power conversion efficiency under 100 mW/cm2. Our cell performances are still low, but higher cell conversion efficiency is expectable when the solar cell devices are fabricated in the glove box.
Subjects
單層異質接面
富勒烯
異質接面
太陽能電池
bulk-heterojunction
fullerene
heterojunction
polymer
solar cell
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-96-R94549008-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):c3bb34f1d9059adf6ab03706125a1cab