Better Solvents Could Lead To Cleaner, Greener Perovskite Solar Cells

Regardless of appearances, almost all scientific progress comes at a price. That which is hailed as a breakthrough technology that will save the planet or improve the lots of those living upon it almost always comes at a cost, which sometimes greatly outweighs the purported benefits of the advancement.

Luckily, though, solving these kinds of problems is what scientists and engineers live for, and in the case of the potentially breakthrough technology behind perovskite solar cells (PSCs), that diligence has resulted in a cleaner and safer way to manufacture them. We’ve covered the technology of perovskites in the past, but briefly, as related to photovoltaic cells, they’re synthetic crystals of organometallic cations bonded to a halide anion, so something like methylammonium lead tribromide. These materials have a large direct bandgap, which means a thin layer of the stuff can absorb as much solar energy as a much thicker layer of monocrystalline silicon — hence the intense interest in perovskites for cheap, easily manufactured solar cells.

The problem with scaling up PSC manufacturing has been the need for volatile and dangerous solvents to dissolve the perovskites. One such solvent, dimethylformamide (DMF), commonly used in pharmaceutical manufacturing and often a component of paint strippers, is easily absorbed through the skin and toxic to the liver in relatively low concentrations. Another common solvent, γ-butyrolactone (GBL), is a precursor to γ-hydroxybutyric acid (GHB), a common recreational club-drug known as “liquid ecstasy”.

In a recent paper, [Carys Wrosley] and colleagues at Swansea University showed that γ-valerolactone (GVL), a far less toxic and volatile solvent, could be effectively substituted for DMF and GBL in perovskite manufacturing processes. One of the most promising features of perovskites for solar cells is that the solution can be easily applied to transparent conductive substrates; the use of GVL as a solvent resulted in solar cells that were comparably efficient to cells made with the more dangerous solvents.

[Featured images: Swansea University, Solliance Solar]

18 thoughts on “Better Solvents Could Lead To Cleaner, Greener Perovskite Solar Cells

  1. The health risk is meaningless when it comes to scaled production. All that matters is $/kwh lcoe with all costs accounted for. If this stuff is safer but costs 10x, then it might be cheaper to keep the toxic solvent and make employees wear ppe’s.

    1. This is the type of thinking that makes people continue to use fossil fuels as the polar ice caps melt. The REAL cost is not money. Money is just an arbitrary system for exchanging goods and services. When facing death, the real cost is your life. Forget about the money and save yourself! Or feel free to die while grasping at your dollars, just leave the rest of us out of your death cult.

      1. Maybe if we calculate reduction of expected lifespan and calculate the loss of income for that period, you could get the monitary cost for use of unhealthy chemicals or destroying the environment.

      2. This is the type of thinking that dominates all commerce. It makes no difference who thinks it’s a great idea if it cannot compete with current fossil fuels or even current pv panels, it will die. That’s because everything costs money and if no one will buy your panels because they cost x times more, then how will you force adoption of it? Will you build them with your own money and give them out for free?

        1. Subsidize and let it get cheap through mass production, or get rid of harmful industries and use the surplus of real resources from that. Tax bitcoin mining and I’m sure you’ll find a few bucks for your green solvent or totally sealed PPE spacesuits.

          1. Subsidies don’t do away with the cost, they just shift it somewhere else.

            Things that cost more money also cost more resources through the increase in economic activity necessary to support them – OR – they cause a reduction in living standards by redistributing resources from other activities. In other words, increasing the cost of stuff by forcing more expensive means of production through subsidies also increases poverty in general, which then shows up as social problems, illness, and loss of life.

            “Subsidize and let it get cheap” never actually happens. The prices will stay at exactly the level you’re paying because there is no reason for anyone to sell for any less. It’s only when you withdraw subsidies that real development can happen, because the companies have to compete for buyers.

    2. Does your employer have a “death in duty” policy? Workplace insurance to pay? A risk of being sued if they put employees in danger? How much money do they put into hiring?

      There’s usually a monetary cost to poor safety, though that may not be the case in all countries.

    1. GBL is hard to import and there’s all kinds of controls and paperwork thanks to it being a precursor.
      Also, the human liver can make GHB from GBL, so it is a drug in it’s own right.
      That makes for PR and practical problems for production.

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