Analysis of the losses of industrial-type PERC solar cells

The loss analysis of state-of-the-art p-type Czochralski-grown silicon passivated emitter and rear solar cells (PERC) fabricated in a manner close to industrial production is presented in this paper. The 6-inch solar cells are featuring a homogeneous emitter on the front side, an Al2O3 passivation layer and local contacts on the rear side. The peak energy conversion efficiencies obtained are 21.1% for a standard antireflection coating (ARC) and 21.4% for a double-layer ARC. The loss analysis is based on an extended characterization of the solar cells and of special samples, which allow the separation of the contributions of each region of the solar cell including metallization. Their impact is determined experimentally on the open-circuit voltage, the short-circuit current density, and the fill factor. Based on the measurements, the devices are numerically simulated. The free energy losses are analyzed using the simulation model. Based on the results from the loss analysis, it is found that the integration of a selective emitter structure and the further improvement of the rear surface would allow for efficiencies above 22% in the short term.