Researchers at the International Solar Energy Research Center (ISC) Konstanz and the Delft University of Technology have found a way to pattern the rear end of an Interdigitated Back Contact (IBC) cell to enhance the efficiency of the solar cells by making some parts of it thicker.

The researchers developed a novel technique to pattern the backside or the rear end of IBC solar cells through a laser doping process, which enhances oxidation in selected areas.

The team found that this led to a more efficient patterning while also serving as a protective layer for further manufacturing steps. This offers the potential for scaling up manufacturing and thus commercializing solar technology.

The new method utilizes enhanced oxidation properties under locally laser-doped regions with high phosphorus concentrations, achieved by phosphosilicate glass layers. The method holds promise for making these cells more efficient.

Since the first IBC cells were developed in the early 1970s, they have been extensively used as the back or non-illuminated side of solar cells.

When compared to conventional both-side contact solar cells, the advantage of IBC cells is that they eliminate any optical shading losses caused by the metal finger and bus bars on the front side. This allows the solar cells to boast a higher short-circuit current density and reduces the complexity of cell interconnection inside the module.

Due to this, a more comprehensive range of front surface texturing and light trapping schemes can be utilized on the front surface of the IBC structure. This design architecture makes it a perfect component for mechanically stacked tandem cells with higher-bandgap technologies, like perovskites.

Germany-based Fraunhofer Institute for Solar Energy Systems also obtained a record conversion efficiency rate of 26% for both-sided-contacted silicon solar cells in 2021, which is preferred across industrial production owing to their lower complexity.

Last September, researchers from Fraunhofer Institute for Solar Energy Research ISE (Fraunhofer ISE) and NWO-Institute AMOLF also developed a multijunction solar cell with a record 36.1% efficiency. This method stacked up multiple layers of light-absorbing materials on top of each other, allowing each layer to capture specific segments of the sunlight’s color spectrum efficiently.