Imec claims 22.8% efficiency for bifacial n-type PERT solar cell

Imec's bifacial n-PERT solar cell

Belgian micro and nanoelectronics research center Imec announced it has developed a bifacial n-PERT solar cell with front-side conversion efficiency of 22.8%.

The research institute said that the cell has an average conversion efficiency of 22.4%, with the best cell topping 22.8%. Imec said the result was internally measured based on a calibrated reference cell used by the photovoltaic calibration laboratory at the Fraunhofer ISE (CalLab), without specifying whether it was confirmed by an independent entity.

Imec said the cell has thin and narrow (< 20 µm) nickel-silver (Ni/Ag) plated fingers on both of its p+ and n+ sides, and that the cell contacts were manufactured in a patented process of simultaneous plating both cell sides. “This cell plating – Imec added – is performed on cassette level (simultaneous plating on a full cassette of wafers in a chemical bath) without the need for an electrical contact to be made to the substrates.”

The research institute claims that this new cell technology has the potential for a low cost-of-ownership at module level, less than $0.30/W. In particular, Imec cites the very limited use of silver, along with the potential for multi-wire interconnection schemes, as the main factors that could lead to a low cost production process.

“As for the bifacial aspect: our cells have a near 100% bifaciality, which maximizes the bifacial gain. We are now working to demonstrate this technology on full 60-cell modules with wire interconnection, which we expect will reveal the full potential of this promising bifacial technology on an industrial level,” said Imec engineer Filip Duerinckx.

Imec announced a 22.02% efficiency for its n-type PERT cell in January 2015. Later in April 2016, the institute said it was able to apply its PERT technology to an n-type wafer developed by Californian technology company Crystal Solar. The result announced by imec and Crystal Solar saw156x156mm2 PV PERT cells produced using a wafer manufactured using the Direct WaferTM process, achieving a conversion efficiency of 22.5%.