Advance of Sustainable Energy Materials: Technology Trends for Silicon-Based Photovoltaic Cells

Abstract

Modules based on c-Si cells account for more than 90% of the photovoltaic capacity installed worldwide, which is why the analysis in this paper focusses on this cell type. This study provides an overview of the current state of silicon-based photovoltaic technology, the direction of further development and some market trends to help interested stakeholders make decisions about investing in PV technologies, and it can be an excellent incentive for young scientists interested in this field to find a narrower field of research. This analysis covers all process steps, from the production of metallurgical silicon from raw material quartz to the production of cells and modules, and it includes technical, economic and environmental aspects. The economic aspect calls for more economical production. The ecological aspect looks for ways to minimise the negative impact of cell production on the environment by reducing emissions and using environmentally friendly materials. The technical aspect refers to the state of development of production technologies that contribute to achieving the goals of the economic, environmental and sustainability-related aspects. This involves ways to reduce energy consumption in all process steps, cutting ingots into wafers with the smallest possible cutting width (less material waste), producing thin cells with the greatest possible dimensional accuracy, using cheaper materials and more efficient production. An extremely important goal is to achieve the highest possible efficiency of PV cells, which is achieved by reducing cell losses (optical, electrical, degradation). New technologies in this context are Tunnel Oxide Passivated Contact (TOPcon), Interdigitated Back Contact Cells (IBCs), Heterojunction Cells (HJTs), Passivated Emitter Rear Totally Diffused cells (PERTs), silicon heterojunction cells (SHJs), Multi-Bush, High-Density Cell Interconnection, Shingled Cells, Split Cells, Bifacial Cells and others. The trend is also to increase the cell size and thus increase the output power of the module but also to reduce the weight of the module per kW of power. Research is also focused to maximise the service life of PV cells and minimise the degradation of their operating properties over time. The influence of shade and the increase in cell temperature on the operating properties should preferably be minimised. In this context, half-cut and third-cut cell technology, covering the cell surface with a layer that reduces soiling and doping with gallium instead of boron are newer technologies that are being applied. All of this leads to greater sustainability in PV technology, and solar energy becomes more affordable and necessary in the transition to a “green” economy.