The Belgian nanoelectronics research center Imec has developed a very efficient bifacial n-PERT (BiPERT) solar cell technology with a bifaciality factor of nearly 100%. The cell efficiency at the rear is nearly as high as the efficiency at the front.
 
Bifacial solar cells capture not only the light falling on the front of the solar panel, but also the light falling on the rear – including light reflected from clouds or the background, diffuse light, and even direct light at sunrise and sunset. Bifacial module are therefore able to generate more electricity than conventional monofacial modules.
 
The first experimental batch of BiPERT cells exhibited very high bifaciality factors. At 39.8 mA/cm², the current from the back side was 97% of the current from the front side (41.2 mA/cm²). Under standard test conditions the cells achieved an efficiency of 22.6%, with only the front side illuminated and no reflective back panel present. Imec ultimately expects to achieve an efficiency of 26% with a modest bifacial gain of just 15%.