Many solar technologies do not use certain parts of the spectrum, but scientists in Australia and the United States are promoting the development of photovoltaic cell sensitivity, converting low-energy light into more energetic visible light that can excite silicon. The researchers used oxygen as a photoconversion catalyst to achieve this through photochemical "upconversion".
Although systems have been developed to up-convert light at near-infrared photon energy, up-conversion below the silicon band gap has not been achieved. Researchers from the University of New South Wales, Sydney and scientists from RMIT University and the University of Kentucky recently explained in "Natural Photonics" that they demonstrated an up-conversion composition that uses semiconductor quantum dots to absorb low-energy light and use Molecular oxygen transfers light to organic molecules.
University of New South Wales professor Tim Schmidt said that one method of upconverting light is to capture multiple photons of smaller energy and stick them together. Schmidt explained: "This can be achieved through the interaction of excitons. Excitons are the bound state of electrons. Electrons and holes can transport energy but not net charge."
To expand the sensitivity range of solar cells, the researchers used oxygen, which is usually harmful to molecular excitons. However, they demonstrated that oxygen can mediate energy transfer, allowing organic molecules to emit visible light above the silicon band gap.
Professor Jared Cole from RMIT University said: “The interesting thing is that many things work without oxygen. Once you allow oxygen to enter, they stop working. This ruined all our plans. Achilles heel, but now, not only have we found a way to bypass it, it suddenly helped us."
The researchers used the PBS semiconductor nanocrystal sensitizer to absorb photons below the silicon band gap and fill the three states of violanthrone below the singlet oxygen energy. After the energy transfer of the two singlet oxygen molecules, the three-state violet group emits light in the visible spectrum.
Lead author Elham Gholizadeh of the University of New South Wales Sydney said: "Lucanthone does not have perfect photoluminescence quantum yield, so the next step will be to find better molecules. But I am very hopeful and think we can increase efficiency quickly. ."
According to the investigation of the micro-lithium battery group, because the efficiency is still very low, the scientists said that to apply this technology to commercial solar cells, a large amount of material development is needed.
Guangzhou Jointair Co., Ltd. , https://www.nbjointair.com