OFweek Solar PV Network Translation: Solar power generation must achieve higher efficiency and lower costs to compete with fossil fuel power generation. Currently, silicon-based solar cells are the dominant technology in the solar energy field, but their high cost hinders their widespread adoption. Solar cells using inorganic nanocrystals or quantum dots are cheaper, but their conversion efficiency is not high enough.
Researchers at the Technion – Israel Institute of Technology have developed a new method for generating electric fields in quantum dots, which is better suited for making high-efficiency nanocrystalline solar cells.
In a report published in Nature Materials on October 9, Professor Nir Tessler and colleagues at the Technion – Israel Institute of Technology described how they tuned the electrical properties of quantum dots and then tested their performance in a solar cell model.
Quantum dots are extremely small semiconductor nanoparticles, so based on quantum mechanics, the energy of electrons that can exist within them is very limited. The energy level determined by the size of the quantum dot, in turn, determines the band gap. By controlling the size of the quantum dot, the band gap width can be easily adjusted without changing the material or fabrication process. Quantum dot solar cells are an emerging field of solar cell research, using quantum dots as photovoltaic materials instead of silicon, CIGS, or CdTe.
Given their unique electronic properties, nanocrystals, or quantum dots, are promising materials for the fabrication of low-cost, high-efficiency solar cells, Tessler said. The size of quantum dots is closely related to their light absorption, so changing the size of quantum dots can increase their light absorption rate in solar cells.
However, the efficient sharing of electrons in quantum dots has always been difficult to control. Researchers at the Technion – Israel Institute of Technology have invented a new method to introduce charge into quantum dots.
Tessler and colleagues generated a strong electric field in quantum dots by wrapping them with two different organic molecules.
