The solar energy critics usually point fingers at its efficiency.
Researchers in Japan however are combining various polymer and molecular semiconductors together as photo absorbers to create a solar cell with increased efficiency.
Many other laboratory works are also going on around the world, in a bid to increase the efficiency of solar panels and cells.
Present Solar Efficiency
I can say the efficiency of present day cells and panels are relatively low.
`Solar panel efficiency is generally between 15 to 20 percent.
Solar cell efficiency can however reach up to 42% in some cases.
It is worthy of note that, most solar cell performance are measured under laboratory conditions.
|SOLAR PANEL TYPE||EFFICIENCY|
|Monocrystalline Solar Panels||The current delivered monocrystalline solar panel efficiency stands at 22-27%|
|Polycrystalline Solar Panels||The current delivered polycrystalline solar panel efficiency stands at 15-22%|
|Thin Film Solar Panels||thin film cells deliver between 15-22% solar panel efficiency|
Polymer and Molecular Semiconductors for Increased Solar Efficiency
Researchers, based in Hiroshima University of Japan, blended a collection of polymer and molecular semiconductors as photo-absorbers to create a solar cell with increased efficiencies in terms of electricity generation.
These cells so developed are known as “organic photovoltaic cells” (OPV)
OPV devices generates electric current when light rays are incident on the phot absorbers.
To measure the efficiency of solar cells a “photon harvest” test is conducted.
“A photon harvest” is a test conducted to know or estimate the efficiency of solar cell, by comparing how much electricity is generated to how much light that is incident on the cell.
That is trying to answer the question “what fraction of indecent light rays are converted to useful electricity?”
The more efficient the solar cells are the more useful they are for commercial production.
The team at the Graduate School of Advanced Science and Engineering added only a small amount of a compound that absorbs long wavelengths of light resulting in an OPV that was 1.5 times more efficient than the version without the compound.
The compound was able to enhance the absorption intensity due to the optical interference effect within the device.
The group went on to show that how they are distributed is key to further improved power generation efficiency.
“The addition of a very small amount of a sensitizer material to an OPV cell, which consists of a semiconducting polymer that we developed previously and along with other materials”
“This leads to a significant increase in the photocurrent and thereby the power conversion efficiency due to the amplified photon absorption that originates in the optical interference effect. A key is to use a very specific polymer, one that allows us to have a very thick semiconductor layer for OPV cells, which significantly enhances optical interference effect compared to a thin layer.”Itaru Osaka, corresponding author of the paper, published November 2020 in Macromolecules
While speaking about the future of OPV Itaru Osaka said:
“Our next step is to develop better semiconducting polymers as the host material for this type of OPV and better sensitizer materials that can absorb more photons in the longer wavelength regions. This would lead to the realization of the world’s highest efficiency in OPV cells.”