An ultra-thin graphene layer could help protect next-gen solar panels

Graphene, the wonder material composed of a single layer of graphene atoms arranged in a honeycomb-like, hexagonal pattern, is capable of everything from health tracking to filtering the color out of whiskey. Now researchers have discovered the latest technological magic trick in its arsenal: Helping to safeguard perovskite solar cells from damage.

Over the past decade, perovskite solar cells have proven their worth as an exceptionally promising solar cell material. One of perovskite’s big advantages is that it can be made into a liquid coating that can then be sprayed onto a substrate material to create solar cells at high volume and significantly lower costs than traditional silicon solar cells. The disadvantage of these perovskite solar cells is that they are not especially durable, which poses a problem when it comes to solar cells that are used in outdoor environments, which are frequently exposed to the elements.

That’s where graphene comes in. Among its many abilities, graphene is exceptionally strong. Previous demonstrations have shown how a two-layer epitaxial graphene film is able to withstand perforation by a diamond tip, making it an exceptionally good material for lightweight, ultrathin armor. In the case of this latest solar cell demo, engineers from South Korea’s Ulsan National Institute of Science and Technology (UNIST) demonstrated how graphene’s useful combination of strength, transparency, and electrical conductivity makes it a great addition to perovskite solar cells by protecting them while letting through photons of light and electrons, but blocking metals ions.

Although there is a slight reduction in power conversion efficiencies — 16.4% with the graphene armor versus 17.5% without — this is marginal next to the advantages the coating brings. The graphene-augmented solar cell was able to retain its efficiency even after 1,000 hours of operation.

In an abstract describing the work, the researchers note that: “In perovskite solar cells (PSCs), metal-induced degradation with the perovskite layer leads to various detrimental effects, deteriorating the device performance and stability. Here, we introduce a novel flexible hybrid [transparent conductive electrodes] consisting of a Cu grid-embedded polyimide film and a graphene capping layer, named GCEP, which exhibits excellent mechanical and chemical stability as well as desirable optoelectrical properties.”

A paper describing the research was recently published in the journal Nano Letters.

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