Progress in crystalline silicon heterojunction solar cells

Abstract

At present, the global photovoltaic (PV) market is dominated by crystalline silicon (c-Si) solar cell technology, and silicon heterojunction solar (SHJ) cells have been developed rapidly after the concept was proposed, which is one of the most promising technologies for the next generation of passivating contact solar cells, using a c-Si substrate and two hydrogenated amorphous silicon (a-Si:H) thin films. SHJ solar cells not only have the advantages of high conversion efficiency and high open-circuit voltage, but also have a low temperature coefficient and free from potential induced degradation. For SHJ solar cells, the passivation contact effect of the c-Si interface is the core of the entire cell manufacturing process. To approach the single-junction Shockley–Queisser limit, it is necessary to passivate monocrystalline silicon well to reduce the efficiency loss caused by recombination. Recently, the successful development of silicon heterojunction technology has significantly increased the power conversion efficiency (PCE) of crystalline silicon solar cells to 27.30%. This review firstly summarizes the development history and current situation of high efficiency c-Si heterojunction solar cells, and the main physical mechanisms affecting the performance of SHJ are analyzed. Subsequently, an overview is provided on the selection and application of passivation contact layer materials, with particular emphasis on distinguishing between various types of passivation materials and their respective roles in facilitating selective carrier transportation. Then, other components of SHJ solar cells are reviewed, including the selection and application of transparent conductive electrode materials that can reduce or replace indium element use. The application of copper plating technology and laser transfer printing (LTP) technology in the industrial development of SHJ solar cell technology is discussed. Finally, the development status of SHJ-based tandem solar cells is discussed, and also the prospects, challenges, as well as potential solutions for industrial development of SHJ solar cells are outlooked.