Cost-efficient plastic solar cells are now one step closer to the market thanks to new research from Imperial College London — a new means of exerting control over the arrangement of polymer molecules within a thin layer of a plastic solar cell has been developed, allowing, essentially, the creation of ‘nanowires’ within the material.

One of the primary obstacles to the creation of cheep, efficient plastic solar cells has been the difficulty in controlling the arrangement of polymer molecules within the thin layer of the printed polymer semiconducting material — a difficulty that now appears to have been overcome. The researchers at Imperial have developed “an advanced structural probe technique to determine the molecular packing of two different polymers when they are mixed together.”

“By manipulating how the molecules of the two different polymers pack together, the researchers have created ordered pathways — or ‘nanowires’ — along which electrical charges can more easily travel. This enables the solar cell to produce more electrical current.”

“Our work highlights the importance of the precise arrangement of polymer molecules in a polymer solar cell for it to work efficiently,” states Ji-Seon Kim, lead researcher and also a senior lecturer in experimental solid-state physics at Imperial College London. Kim also mentions that she expects polymer solar cells to hit the commercial market sometime within the next 5 to 10 years.

The obvious advantage of such polymer solar cells is that they have the potential to be significantly cheaper to produce than conventional solar cells — which typically require expensive, highly purified silicon. The cost savings that could result from replacing that silicon with polymers could be enormous.

The researchers explain: “Organic semiconducting materials, and especially polymers, can be dissolved to make an ink and then simply ‘printed’ in a very thin layer, some 100 billionths of a meter thick, over a large area.”

“Covering a large area in plastic is much cheaper than covering it in silicon, and as a result the cost per Watt of electricity-generating capacity has the potential to be much lower,” states Kim.

The new research was just published in The Journal of Chemical Physics.