Solar energy from windows, roofs and clothes

Researchers from the Department of Chemical Sciences at the University of Arizona, USA, are trying to bring about a conceptual revolution regarding renewable energy

Dr. Moshe Nahamani
Researchers from the Department of Chemical Sciences at the University of Arizona, USA, are trying to bring about a conceptual revolution in renewable energy. The scientists are conducting research aimed at making flexible and thin solar cells that can supply electricity to a tent or charge our car while it is in the parking lot. "The sun is clean and free. Why not use it?" wonders the lead researcher.

Across the university, professors, scientists, students and others involved in policy planning and economic analysis are working to raise this question for public debate. On the university grounds, where sunlight is widespread and powerful, they try to deal with problems such as: how to utilize solar energy on an industrial scale, how to use it to charge cheap electrical products such as mobile phones, laptops and music players, and what to do at night or when the sky is covered with clouds .

"The interest in renewable energy is a perfect place to demonstrate that we don't know where the next breakthrough will occur," said Leslie P. Tolbert, vice president for research at the university. "Somewhere, in some lab, there's someone discovering a whole new way to capture sunlight. In fact, there are many people doing just that. And even they rely on a team of basic science researchers who have produced new information to feed their thoughts."

Since his early days as a student during the first Arab oil boycott in 1973, researcher Armstrong has witnessed a series of distress calls from the administration regarding the energy sector. One of those readings led him to discover the research of two researchers in Germany. They figured out how to fix color separations on metal oxide surfaces and break down water using solar radiation. "I thought to myself, this is exactly it - this is what I'm going to do in my career from now on."

The next call came to him four years ago. "The Ministry of the Environment began to feel that the ground was burning under its feet, and in a big way," explains the researcher. "And they were worried that they didn't know what to do exactly—how to present the problem to Congress in a way that would lead to additional funding and be an important area of ​​research."

Armstrong realized that the time had come to return to the problem he wanted to investigate thirty years ago. "Now, we are properly equipped," he notes. "We learned how to simulate particles at the molecular level, how to measure energies of thin surfaces, how to prepare devices and how to collaborate with physicists and materials science researchers."

In his office, the scientist presents an example from his research: a two-and-a-half-centimeter square glass surface covered with a thin layer of tin-indium oxide, a conductive transparent oxide commonly used in display surfaces such as computer monitors. On this layer there is a thin layer of organic dye. The outer layer is a ceramic (aluminum) electrode.

"So you have a plastic roll containing solar cells on the outside. The idea is that you can go to any major chain store and buy this roll. Next, you can simply spread it on any surface, such as a window, a roof, your car or even the clothes you wear. It Contains two power cords attached to it and can connect to your battery or laptop and charge them."

"The total thickness is only approximately four hundred nanometers. And yet, if you shine light on it, you can get electricity from it. Now, we are interested in reducing its thickness even more. We need to reduce its thickness even more to get the most electrical energy possible. However, if you Thinking of it as a kind of structure of a sandwich, we were able to make an extremely thin sandwich where each of the layers connected to each other must be precise in terms of chemical composition, separate directionality and strength of fixation to the different surfaces.

The equipment available today—optical microscopes capable of "seeing" individual particles and revealing their electronic properties and spatial orientation—helps his research team gain a more comprehensive understanding. Their ultimate goal is to understand how to get mares to organize themselves - time and time again - in a way that will provide the most electricity possible. "They all have to get along like a highly organized order of soldiers."

A high-vacuum photoelectric spectrometer allows researchers to build each and every molecular layer, move it around in a vacuum for examination, and then continue with another layer. Additional tools, such as a silicon microtip, which looks like a turntable needle, can operate with an accuracy of plus/minus 0.01 nanometers. "Precisely he is within the diameter of a single female," explains the researcher. Passing a laser through the tip is able to provide an image, and by passing an electric current through the tip the researchers are able to map the electronic properties of the particles. These tools, together, allow the researchers to prepare a template for creating the optimal structure of the various separate arrangements.

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