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Researchers at the Georgia Institute of Technology have developed 3D photovoltaic fiber solar cells. This is a revolutionary new development. It has done a good job laying the ground for a new generation of ultra-flexible solar energy systems.
Renewable energy and green energy are the driving forces for future economic development. As one of the important sustainable energy technologies, solar cells will become the main energy source to meet the global demand for energy. Among various types of solar cells, dye solar cells have been widely used for their high cost performance.
Traditional dye solar cells use nanoparticles and nanowires to increase their photoelectric conversion efficiency. However, these are based on two-dimensional planar structures, which limits the further improvement of the efficiency of such photovoltaic cells. The research team led by Professor Wang Zhonglin from the Georgia Institute of Technology in the United States has developed a three-dimensional dye solar cell combining nanotechnology and fiber technology. Its unique three-dimensional structure greatly improves the photoelectric conversion efficiency of similar solar cells. This latest result was recently published in Angewandte Chemie in Germany.
Prof. Wang Zhonglin, Dr. Wei Yaguang and graduate student Benjamin Wembley combined solar cell structure and fiber technology to realize the design of three-dimensional photocells using nanostructures. The three-dimensional dye solar cell main structure of the mixed structure of the optical fiber and the nanowire includes an optical fiber and a zinc oxide nanowire array vertically grown on the surface of the optical fiber (as shown in the figure). The sunlight is incident axially from one end of the fiber and propagates. The core design idea of ​​a three-dimensional solar cell is that the incident light is reflected multiple times during propagation in the fiber. During each reflection, the incident light interacts with the dye attached to its surface through the zinc oxide nanowires. Multiple reflections increase the number of interactions of dyes on the surface of incident photons and nanowires, which greatly increases light absorption and photoelectron transport efficiency. The experimental results show that for the same three-dimensional dye solar cell, compared with light irradiation on the fiber side wall, the light propagation delays the energy transfer efficiency of the solar cell by six times. Under a solar (AM 1.5) illumination, the photoelectric conversion efficiency of a three-dimensional dye solar cell based on zinc oxide nanowires reached 3.3%. This efficiency is 120% higher than that of the previously reported two-dimensional dye solar cell of the same type, and 47% higher than that of a dye solar cell using a zinc oxide nanowire coated with a titania film.
The new three-dimensional dye solar cell has the following outstanding features in scientific research and practical application. From a physics perspective, nanowire-based two-dimensional dye solar cells have a small surface area, which limits the loading of dyes and the absorption of sunlight. Increasing the length of the nanowires can increase the surface area, but the length of the nanowires is limited by the length of material preparation and electron diffusion. The unique structure of the three-dimensional dye solar cell overcomes the above difficulties: the incident sunlight is reflected multiple times in the optical fiber, interacts with the dye on the surface of the nanowire multiple times without increasing the electron transport distance, and greatly increases the absorption of light. And photoelectron transport efficiency. In application, three-dimensional dye solar cells have the following main advantages: First, the use of optical fibers enables solar cells to work remotely and with high mobility. It can work in the strata and deep in the ocean where sunlight can not reach; secondly, three-dimensional dye solar cells can have smaller dimensions, higher efficiency, greater mobility, more reliable design, more flexible shape, and It is possible to reduce production costs. Third, three-dimensional dye solar cells can work effectively under different light intensities and have a high dynamic operating range. The research results have opened up new methods and ideas for designing three-dimensional high-efficiency multi-functional solar cells using optical fibers and hybrid structures of organic and inorganic materials.
A schematic diagram of the structure and basic working principle of a three-dimensional dye solar cell with a mixed structure of optical fibers and nanowires. A) A three-dimensional dye solar cell includes an optical fiber and a zinc oxide nanowire array vertically grown on the surface of the optical fiber. In the upper part of the figure, the traditional optical fiber is used for the long-distance transmission of light, and the lower half is the solar cell for photoelectric conversion. B) Detail structure of a three-dimensional dye solar cell.
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