Hebrew University researchers have succeeded in improving the function of solar cells

Provoskite, a semi-conducting material that was recently discovered by Prof. Lioz Etgar and his team from the Hebrew University as being very effective in absorbing sunlight, and whose refinement may lead to dramatic changes in the global use of solar energy, is now turning out to be a material that can be replaced in solar cells without waiting for it to break down or be destroyed and thus harm the environment

Solar energy is considered a green and non-polluting trend, allows relatively maximum utilization of the sun's energy, is available everywhere and does not need to be transported from place to place - but despite this, the question still arises, do solar cells only have a positive effect on the environment? Today it is known that after the end of the solar cell's life, the materials that make it up may break down and create environmental pollution. Prof. Lioz Etgar from the Institute of Chemistry in the Faculty of Mathematics and Natural Sciences at the Hebrew University recognized the challenge, and in his laboratory solar cells were developed which were discovered to be capable of cycling. The unique structure of these cells gives them stability that allows them to be washed, to remove the active material perovskite from them and to put a new, fresh material in its place. The researchers found that the efficiency of the cells is fully maintained even after the application of the new perovskite for the second and third time, as well as after several additional cycles.

Prof. Etgar's discovery, described in detail in PNAS, the official journal of the National Academy of Sciences of the United States, makes it possible to proactively replace the perovskite in the solar cell, without waiting for it to be destroyed or disintegrated. "Think, for example, of a roof coated with solar cells or a field of solar cells - after a certain period of time, when the usefulness of the cells decreases, it will be possible to wash them of the perovskite material, while the rest of the cell pattern remains and is not damaged. In the next step, new perovskite can be applied into the existing cells. This is a simple, efficient, cheap process and of course does not harm the environment," the researcher explained this week.

In the scientific article it was stated that there is a prominent advantage of these solar cells - the ability to print the cells in full using a method called screen printing, which allows the creation of large and uniform solar panels and the reduction of their cost. Another advantage is their high efficiency which characterizes the perovskite cells and very good stability due to the structure consisting of a network of oxidized metals which are known for their excellent stability. 

Renewable energies have recently played a central role in the advancement of humanity, including solar energy and wind energy. In the field of solar energy, perovskite-based solar cells have reached high efficiency in just a few years, which places this technology as a leader among existing solar energy technologies. Perovskite is a light-sensitive material, when by irradiating it in sunlight it can produce charges from which electricity can be produced. This material is simple to prepare, has excellent conduction properties and broad absorption of light. The researchers are convinced that this unique technology can be used for several applications, including semi-transparent cells and cells that can be used as complementary cells to existing technologies such as silicon-based solar cells.

In the previous study, Published in the scientific journal Nano Letters, Prof. Etgar's research group created a two-dimensional perovskite for the first time. The two-dimensional perovskite is more stable than the perovskite used so far in solar cells. The issue of the stability of the solar cells is extremely important, in order for this technology to be commercialized. In the laboratory, the researchers were able to integrate the two-dimensional probe into the solar cell, and as a result, high efficiency of the cells was obtained, their stability improved and their overall cost decreased significantly. In addition, and perhaps most importantly, they were very effective in absorbing the sun's energy - energy that is not being used in an efficient and useful way today. In fact, there is a huge gap between the existing use of solar energy and its unused potential.

for the scientific article