Organic Solar Cells: Recent Developments
Substantial advances in the properties of OPV cells were published earlier this month in Nature Communications. The research was performed by Dr. Kaltenbrunner and his coworkers, from the Department of Soft Matter Physics, at the Johannes Kepler University of Linz (Austria), in cooperation with the Linz Institute for Organic Solar Cells (LIOS) and Exploratory Research for Advanced Technology (ERATO). The OPV cells made in this study have a thickness of only 1.9 mm; furthermore, the device is very flexible and stretchable.
Composition of New OPV cells
In the OPV cell, the active layer is made of a mixture of poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl-C61-butyric acid methyl ester (PCBM); its thickness is 200 nm. It is placed between the two electrodes, made of poly(3,4-ethylenedioxythiophene):poly(styrenesulphonate) (PEDOT:PSS) and metallic calcium and silver respectively. The substrate is polyethylene terephthalate (PET), a very light and flexible plastic material. A scheme of the solar cell can be seen in the figure to the left.
Why are these results so significant? Decoded Science asked Dr. Kaltenbrunner, and he explained:
“Because our solar cells are so thin, they are much more flexible than other ones previously tested. We could wrap the solar cell around a human hair, with a radius of 35 mm; this is something really amazing. Furthermore, they can be compressed to half of their original length.
Their light weight (only 4 g/m2)is also a very important point. As their efficiency is about 4%, this means that for each gram of these cells we can produce 10 W of energy. This is the highest value of any solar cell ever reported. Further tests should be performed before these OPVs can be commercialized; this is, however, a very important step. ”
Revolutionizing Solar Cells
Each new breakthrough in solar technology brings us one step closer to a new energy future. As Earth Day approaches, research such as this reminds us of the opportunities available through harnessing the sun’s energy – opportunities that are now more accessible than ever before.
Kaltenbrunner M. et al. Ultrathin and lightweight organic solar cells with high flexibility. (2012). Nature Communications. Doi:10.1038/ncomms1772. Accessed April 19, 2012.
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