Renewable and sustainable energy is often associated with solar energy, with silicon-based solar cells being the predominant basis of solar panels. However, silicon can be seen as an expensive and ineffective component within solar cells, often relating to its poor conductivity. This has led to research investigating an alternative to silicon-based solar cells through the introduction of perovskite materials.
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The utilization of a perovskite solar cell and a thin metal oxide film to produce a more effective and sustainable solar energy system is an innovation that could revolutionize the solar energy industry with a global appeal to a more sustainable future. This article will provide an overview of the innovative research aiming to advance silicon-based solar cells.
Silicon is the primary component in solar cells, first gaining traction in the 1950s, forming part of the first renewable solar cell technology. They can be referred to as ‘first generation’ solar panels and compose over 90% of the solar cell market.
At its purest crystalline form, silicon is a poor conductor of electricity due to its semiconductor characteristics. Due to this, the silicon found within solar cells has other atoms mixed with the silicon atoms to increase the conductivity levels. This increases silicon's ability to take in solar energy from the sun and convert it into electricity.
One of the challenges of silicon-based solar cells and silicon solar panels includes the cost, which has decreased in price due to the development of new technology and governmental subsidiaries. Regardless, cheaper and more efficient forms of solar power such as organic solar cells would be a welcomed advancement, as current parts are still relatively expensive to produce and purchase, with added concerns of difficult transportation due to the fragility.
Novel research led by a team of collaborating researchers has focused on an alternative to silicon to optimize and maximize solar cells' energy conversion efficiency. The research was published in the journal, Nano-Micro Letters, and consisted of Kanazawa University researchers applying a metal oxide film onto a perovskite solar cell.
First discovered by Russian mineralogist Perovski, in 1839, calcium titanate was renamed perovskite. Materials that have the same crystal structure of this inorganic compound are referred to as perovskite materials. Perovskite materials have recently gained further attention for optoelectronic and photonic device applications. Characteristics include their impressive optoelectronic properties, including tunable bandgap, a high absorption coefficient, more considerable diffusion length, and low processing costs.
The first author of this novel research, Md. Shahiduzzaman explained that "[they] used spray pyrolysis to deposit a front contact layer of titanium dioxide onto a perovskite solar cell. This deposition technique is common in the industry for large-scale applications."
Metal Oxide Films
Metal oxide films are predominantly produced by chemical deposition processes, involving the reaction of a pure metal with a gas at a high temperature as well as a low temperature. The researchers utilized a highly compact titanium oxide film through spray pyrolysis deposition, which works as an electron transport layer for perovskite solar cells.
It was found that while the energy conversion efficiency of perovskite solar cells was enhanced, researchers could potentially further optimize the design to increase the energy conversion efficiency of more than 30% through a multi-layer front contact. This development indicates the potential of this novel technology to be a competitor for silicon-based solar cells.
Computational simulations suggest that the energy conversion efficiency of perovskite/perovskite tandem solar cells could go beyond 30% by a multi-layer front contact. This is close to the theoretical efficiency limit of silicon-based solar cells.
Md. Shahiduzzaman, First Author, Nanomaterials Research Institute, Kanazawa University
Having an increase in the energy conversion efficiency of solar cells could advance the renewable energy industry. With a lack of pollutants or harmful gases associated with this system, a greener future can be envisaged. Solar energy can be seen as expensive and inappropriate for mass global use; however, with high functioning and cheaper materials, this energy source could be a step in the right direction towards reducing the human impact on the Earth.
Future Outlooks of Silicon-Based Solar Cell Replacements
Advancements in nanotechnology have enabled further development of this field with the use of 3D optical-electrical coupled electromagnetic simulations used to analyze optics and the electrical characteristics of solar cells. This ensures the research into producing a competitive alternative to silicon-based solar cells is validated and reliable.
Applications such as photovoltaic technology to factory use enable this innovative research to revolutionize the concept of traditional solar energy. While there are challenges such as perovskite solar cells being based on a lead, which can be toxic, this research illustrates the solar cell energy market gap.
Overcoming these obstacles will enable this promising research to advance solar cell energy past a silicon base and provide an innovative and effective renewable resource.
References and Further Reading
Shahiduzzaman, M., et al., (2021) Spray Pyrolyzed TiO2 Embedded Multi-Layer Front Contact Design for High-Efficiency Perovskite Solar Cells. Nano-Micro Letters, 13(1). Available at: https://doi.org/10.1007/s40820-020-00559-2
Reshmi Varma, P., (2018) Low-Dimensional Perovskites. Perovskite Photovoltaics, pp.197-229. Available at: https://doi.org/10.1016/B978-0-12-812915-9.00007-1
Science Daily. (2021) An industrially viable competitor to silicon-based solar cells is in the works. [online] Available at: https://www.sciencedaily.com/releases/2021/03/210329122524.htm
The Renewable Energy Hub. (2021) What are Silicon Solar Cells | The Renewable Energy Hub. [online] Available at: https://www.renewableenergyhub.co.uk/main/solar-panels/silicon-solar-cells/