Bifacial n-PERT solar cell boasts 22.8% front-side efficiency

April 19, 2017 // By Julien Happich
In partnership with EnergyVille, researchers from IMEC have manufactured bifacial n-PERT solar cells using an industrially-compatible process, yet achieved a record-setting front-side conversion efficiency of 22.8 percent.

Featuring a transparent backside and comparable front- and back contact schemes, bifacial solar cells capture light on both sides of the cell. As a result, they also profit from indirect light, light reflected by the ground and buildings, diffuse light on overcast days, and even direct light at sunrise or sunset, incident on their rear surface.

Used bifacially under standard front illuminations conditions in conjunction with an additional 0.15 sun rear illumination, these cells can produce the equivalent energy of 26.2 percent monofacial cells. At module level, the newly developed bifacial cell technology has a projected low cost-of-ownership under 0.30 $/Wp which further reduces the levelized cost of electricity (LCOE) of large photovoltaic (PV) installations.

Tests indicate that, over the course of their lifetime, such cells may generate 10 to 40% more electricity than traditional monofacial cells (this proportion depends on their bifaciality, the PV installation properties and the reflection of the location). This may result in an estimated LCOE reduction for PV installations of 10 up to 30 percent.

Front and rear-side of imec’s Bi-PERT bifacial cell
with up to 22.8% front-side efficiency and near 100%

IMEC’s bifacial n-type PERT cells (Bi-PERT) feature thin and narrow (20µm) nickel-silver plated fingers on both the n+ and p+ side of the cell. The cells' contacts were fabricated in a patented process of simultaneous plating both cell sides. This cell plating 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.