A Korean research team has developed a technology to make highly-efficient inverted colloidal quantum dot solar cells.
The research team consisting of Professor Kim Jin-young, Professor Park Jong-nam from the Interdisciplinary School of Green Energy at Ulsan National Institute of Science and Technology (UNIST), and student Kim Gi-hwan was able to manufacture highly-efficient solar cells by synthesizing zinc oxide in liquid state, and coating the synthesized material at the top of a quantum dot.
The optical conversion efficiency of the newly-developed solar cells is 4.31 percent, a 1.7-fold increase from the 2.47 percent efficiency of conventional quantum dot solar batteries.
Existing inorganic solar cells have low efficiency in the conversion of sunlight into electricity, despite high manufacturing costs. However, new solar cells are cheaper to make and have high energy conversion efficiency. Those cells can also be used in various fields, since it is possible to fabricate the solar cells in a thin film form.
The production of quantum dot solar cells is made possible by combining diethylzinc that contains high activation energy with zinc oxide in the air, without the need of a high-temperature heat treatment. In addition, low-cost aluminum can be utilized to make electrodes of solar cells instead of expensive gold by inversely changing the structure of the quantum dots and zinc oxide inside the solar battery, and then coating the material on the surface of the electrodes.
Professor Kim said, “I think that we paved the way for the commercialization of quantum dot solar cells, which many consider next-gen solar cells. It is due to the fact that the newly-developed solar cells can be fabricated at a low temperature. On top of that, cheap aluminum can be used to make electrodes.” He added, “The newly-produced solar cells will lead the future solar cell industry. So, Korea will be able to narrow the gap with leading countries in the development of a next-gen organic photoelectric element.”
The study was conducted as part of a joint research project for energy supported by the Ministry of Trade, Industry and Energy, and the Korea Institute of Energy Technology Evaluation and Planning. The research findings were first published online on Feb. 22 by Advanced Materials, a weekly scientific journal covering materials science.