Scientists at the Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) have developed a crystalline solar cell with efficiency greater than 20% using Heraeus metallization paste.
The record cell is based on the combination of two cell design technologies: metal wrap-through (MWT) and passivated emitter and rear cell (PERC). In a joint research project with the Fraunhofer ISE, Heraeus developed a via paste that interconnects the front side and back side of the MWT solar cell. Heraeus also supplied the front-side paste for this project.
In MWT cells, the busbars typically found on the front side of conventional solar cells, are shifted to the back side of the cell, thereby reducing front-side shading and allowing more light to actually hit the cell, Heraeus explains. The reduction of shading increases the efficiency.
In PERC cells, the back side of the cell is designed so that incoming light is reflected back to the wafer, increasing the amount of energy captured from the cell. The combination of these two technologies creates a cell design that significantly increases a solar cell's efficiency relative to conventional solar cell technologies, according to Heraeus.