Special attention was paid to how the world will reach net zero by 2050. Perovskite solar cells have shown promise in improving the performance and efficiency of solar energy harvesting, but the risks environmental issues that arise from the use of toxic lead must be properly considered, says an article published online in the A land newspaper.
To study: Managing the environmental risks of perovskites. Image Credit: foxbat / Shutterstock.com
The push towards net zero
The world is warming at an alarming rate due to human activity. Speaking in December 2020, UN Secretary-General AntÃ³nio Guterres announced that the world must declare a climate emergency until net zero is reached. According to the IPCC, limit the rise in global temperature to 1.5oC will require drastic reductions in carbon emissions, 45% from 2010 levels by 2030.
The fastest way is to decarbonise the energy sector, as it is responsible for 75% of all greenhouse gases. At least 40 to 70% of the energy mix by 2050 must come from wind and solar for the goals to be achievable. However, current technologies have efficiency issues, which facilitates the need to develop new technologies.
Perovskite Solar Cells
To overcome efficiency and performance issues in solar energy harvesting, much research has focused on studying the use of metal halide perovskite materials in photovoltaic solar cells. Perovskites have better power conversion efficiency than conventional silicon-based solar cells. They also have the advantage of being inexpensive.
However, there is a major problem with these materials. Most perovskites contain lead, which is incredibly toxic to humans, animals and the environment. Concerns have been raised over the widespread use of lead-based perovskite materials in photovoltaic cells, highlighting the urgent need to investigate their potential damage to human health and the environment.
The first concerns about the health effects of lead paint were expressed in the early 20e century, but it had little international attention at the time. Since then, lead damage has been well documented. The use of lead has affected the health of several million people over the years, and exposure to lead contaminants is responsible for more than one million deaths per year worldwide and the loss of 24 million people. disability-corrected life years.
Lead has been mined by humans for centuries, with lead water pipes in use since Roman times. In the modern era, lead has been added to petroleum as an anti-knock agent until very recently and as an additive in paint. Lead is still widely used in the electronics industry and in automotive batteries.
Further Reading: Improving Solar Cells with Virgin Graphene on Lead Iodide Films
Lead poisoning can occur through a variety of routes, including inhalation of particles emitted from industrial activities such as smelting, ingestion of contaminated water or food grown in contaminated soil. Exposure can cause damage to vital organs such as the brain and kidneys and ultimately death. Recent studies have shown that low-intensity lead poisoning is a contributing factor in cardiovascular disease.
The widespread implementation of lead-based perovskite solar cells facilitates the urgent need for research and discussion on the human and environmental risks of these materials. Research in A land discussed the problem from an environmental point of view.
Consider the problem of lead-based perovskites
If the solar cell remains intact, the lead perovskite layer is not a problem as there is no route of exposure. However, damaged or poorly designed solar cells can leach lead into rainwater. Over the lifetime of perovskite solar cells, 1 in 100 will fail, demonstrating the potential magnitude of the problem. Lead from broken solar cells on domestic dwellings can seep directly into garden soil, causing health problems for residents and facilitating uptake by plant root systems.
Concerns about leach damage increased when it was discovered that lead perovskites can release soluble forms of lead such as methyl ammonium lead oxide. Of particular concern is the high bioavailability of this compound and studies in exposed cells have revealed massive levels of apoptosis caused by it. Plants can also take up much higher levels of perovskite at a higher rate than common lead contaminants.
Together with evidence from other studies, these factors demonstrate the environmental risk of lead perovskite solar cells. While it is not yet clear whether this will amount to a large-scale human or environmental risk, the high bioavailability of lead perovskite chemicals is cause for concern.
The study identified some methods that can be used to alleviate this problem. These include a more sustainable perovskite design, better management of environmental risks, and the placement of perovskite solar farms away from residential areas and farmland. The study concluded that a precautionary approach should be taken until the true health and environmental hazards of lead-based perovskites are known.
O’Connor, D & Hou, D (2021) Managing the environmental risks of perovskites [online] A land 4:11 | sciencedirect.com. Available at: https://www.sciencedirect.com/science/article/abs/pii/S2590332221006126