Nano Science and Technology in Solar Cells

Energy is a big challenge in the coming decades. The global population is increasing steadily. Not only are there more people in the world, but the worldwide drive to increase living standards have increased individual energy demands. Growing energy needs were typically met by finding new sources of fossil fuels. People have fortunately begun to realize the adverse environmental impact of burning fossil fuels and that this practice cannot be maintained indefinitely, leading to renewed interest in photovoltaic technologies. The discovery of the photoelectric effect brought hope to the objective of helping to fill the world energy needs with an already continuously delivered source. The discovery of the photoelectric effect was the birth of the idea, but it was the development of the crystalline silicon cell that marked the birth of the industry. The cost and inefficiency of these solar panels have prevented them from becoming an economically competitive form of everyday power generation. Cost was reduced with the introduction of amorphous silicon thin-film cells despite slightly lower efficiencies. Their lower manufacturing costs have allowed solar energy to be included in more applications; the costs have not been reduced enough to compete with current grid rates. The current trend in research suggests that the application of nanotechnology may be the awaited break needed to crack this cost barrier. Nanotechnology promises to reduce cost because they require less controlled conditions, which will greatly reduce the cost per cell, and the initial cost of a new cell type. Nanoscience and nanotechnology are being researched and developed to help solve problems that have prevented the use of other promising technologies, and improving efficiencies of those technologies that have been developed. The addition of nanoparticles to the matrix is a possible way to improve electron transport, and nanotubes could be used in conjunction with nanoparticles. The science of interactions and addition of nanoparticles and their function in solar photovoltaic cells is known, but still developing. Nanoscience has produced proof-of-concept photovoltaic cells made of small perfect crystals, rather than large, perfect silicon crystals that are more expensive to produce. However, the step-up to larger scale, practical photovoltaic cells have not been reproduced efficiently and at a reasonable cost for small, perfect crystals not made of silicon. Nano-whiskers are being experimented as new antireflective coating. Sensitizing dyes are being used to increase the range and location of the wavelengths that can be absorbed to be more favorable to sunlight, allowing the use of materials that lack this key characteristic. Quantum dots could be an improvement to these dyes, as the smaller particles will have the added benefit of having multiple electrons created per photon without impeding electron transfer. Recent research has also shown a method to transform optical radiation into electrical current that could lead to self-powering molecular circuits and efficient data storage. The many possible applications of nanotechnology make photovoltaic cells as promising pursuit.Copyright © 2011 by ASME