On the laboratory table: a combination of two types of nanomaterials, with different optical properties
Solar energy is the future, but the technology is still far from perfect. First, photovoltaic cells, or solar panels, lose their efficiency over time, break down and pollute their environment. And even state-of-the-art panels do not utilize the solar energy that hits them with sufficient efficiency. What is the question? How can you expand the field of absorption of solar panels, and use more energy from the sun?
To solve the first problem, Prof. Lioz Etgar from the Institute of Chemistry at the Hebrew University of Jerusalem developed solar cells with a unique structure, based on the perovskite material. The unique structure of these solar cells makes it possible to wash them, remove the perovskite and embed a new one in its place - thus saving the need to manufacture a new panel in its place.
We are trying to learn about the interaction between these two materials and enjoy the properties of both, with the goal of expanding the absorption spectrum of solar panels
But the perovskite alone does not increase the energy conversion efficiency of the solar panel. "In our new research, supported by a research grant from the National Science Foundation, we are trying to pair two types of nanoparticles, both semiconductors with different optical properties - our perovskite and lead sulfide," explains Prof. Etgar.
"While perovskite mainly absorbs electromagnetic radiation in the visible light range, lead sulfide excels at absorbing infrared radiation. We are trying to learn about the interaction between these two materials and enjoy the properties of both, with the goal being to expand the absorption spectrum of the solar panels - from visible light to infrared, And thus enjoy a more efficient utilization of the sun's energy."
Prof. Etgar emphasizes that the energy savings are significant even if only perovskite is used in the solar cells. "The common cells on the market today are based on silicon," he says, "Energically, the new generation of perovskite-based solar cells produce energy that is at least equal to the energy produced from silicon cells. But the ease, simplicity and cost of producing perovskite cells changes the picture: no equipment is needed An expensive and sophisticated edge to produce perovskite cells, you don't need sterile laboratory conditions and clean rooms, and all this significantly lowers costs and makes life much easier. If we manage to increase the efficiency of the cells by adding lead sulphide - that's good. But we are already offering similar efficiency at lower costs, for the manufacturer, the consumer and of course the environment."
Another possible application for the combination of perovskite and lead sulfide is in light emitting devices - which we all use in screens.
"The same principles of solar panels also work in our television and computer," explains Prof. Etgar. "From the experiments we performed in the laboratory, we already see that lead sulfide absorbs infrared light and emits the energy in the visible light range, which means that it is possible to increase the intensity of visible light. When we look at a screen, we see lots of pixels in different colors. The screen is connected to electricity, or a battery, which provide energy that leads to the emission of light. If we manage to shift the infrared spectrum to the visible spectrum, we will have to invest less energy to activate the This screen. The energy saving is not only intended to lower the electricity bill, but primarily to protect the environment. In addition, the perovskite allows us to adjust the energy they emit so that we get color sharpness that cannot be obtained with other materials - which will also improve the image quality."
"I run for fun" says Prof. Etgar. "I normally run about 15 km, and several times a week I run longer runs - up to half marathons. Not to compete, but purely for fun."
