For instance, its wide band gap perovskite, which goes on top of the stack and gets the sunlight first, is just short of its targeted efficiency. The project is already seeing some promising results. “This in turn will allow us to deliver 30 % efficient tandem cells, which is perovskite stacked on perovskite.” More work to be done “Ultimately, our goal is to demonstrate high efficiency on both wide and narrow band gap perovskite cells,” remarks Snaith. The PERTPV project is taking this one step further and stacking perovskite cells on top of perovskite cells. “By stacking cells, you can increase the band range and, in doing so, increase both voltage and efficiency.”Ĭurrently Oxford PV, a spin-off company of Oxford University, is in the process of stacking perovskites on top of silicon, with a commercial product set to hit the market next year. “A solar cell can only produce as much voltage as the band of light it is able to absorb,” he says. Snaith goes on to explain that this feature is important because different bands of sunlight essentially carry different levels of energy. “What this means is that instead of absorbing all the light in a single material, as is the case with silicon, you can stack two or more cells on top of each other and absorb different bands of sunlight.” “You can change the composition of perovskites to absorb different bands of light,” notes Snaith. What perovskite cells have that their silicon cousins don’t is versatility. Stacking cells for increased voltage – and efficiency “When used as an absorber material, perovskites have proven capable of producing highly efficient cells, almost matching the efficiency of traditional silicon cells,” says Henry Snaith, a professor from Oxford University.īut how can perovskite cells compete with the already efficient silicon cells, which also benefit from being produced at scale? The answer, according to Snaith, is to go for higher efficiency – which is exactly what the EU-funded PERTPV project aims to do. Take for instance perovskites, a material type that has the same crystal structure as the mineral composed of calcium titanate. In fact, other materials have the potential to offer higher efficiency, more versatility and better cost-effectiveness. When put together as a solar panel, these cells can create enough electricity to power a home, school or office, or distribute power directly into the electricity grid.Īlthough silicon is the most common material used in solar cells, it’s not the only material. A solar cell, also called a photovoltaic cell, or PV, absorbs sunlight and then uses that energy to generate electricity.

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