Discussion about ultimate efficiency of solar cells

Abstract

Solar energy is considered as one of the most promising green energy due to clean, safe, long life, and renewable advantages. Solar cell is an electrical device that converts solar energy directly into electric power on the basis of photovoltaic effect. Fritts built the first solar cell in 1883. Although the initial efficiency was only 1%, it has been exciting to know that the power conversion efficiency of solar cells is endlessly improved since it was reported. Up to now, the efficiency of commercial silicon solar cell is between 10%–18%. The latest research shows that the best efficiency of perovskite solar cell has been improved to be over 20% within several years. As it is well known, the maximum power conversion efficiency of single-junction solar cells are only around 33% according to the Shockley- Queisser limit. With the development of new materials and high technologies, one issue is emerging: What is the ultimate efficiency of solar cells? The highest efficiency of solar cell is possible to break the Schockley-Queisser limit? How to further enhance the efficiency of solar cell? All the questions are hard to answer at present. Surrounding these concerns, this article presents a brief review about the efficiency limits of different solar cells. It might help to understand the ultimate efficiency of solar cells. The details address the basic principle, advantages and disadvantages of single-junction, multi-junction and other new concept solar cells regarding the power conversion efficiency. The review also includes the solar cell materials involving silicon, compound, perovskite, quantum dot, hybrid materials, etc. Finally, we look ahead into the prospect of new concept solar cells and the maximum power conversion efficiency.