Assessment of the illumination dependency of Al₂O₃ and SiO₂ rear‐passivated p‐type silicon solar cells

This Letter discusses an important difference between positively charged SiO 2 and negatively charged Al 2 O 3 rear‐passivated p‐type Si solar cells: their illumination level dependency. For positively charged SiO 2 rear‐passivated p‐type Si solar cells, a loss in short circuit current ( J SC ) and open circuit voltage ( V OC ) as a function of illumination level is mainly caused by parasitic shunting and a decrease in surface recombination, respectively. Hence, the relative loss in cell conversion efficiency, J SC , and V OC as a function of the illumination level for SiO 2 compared to Al 2 O 3 rear‐passivated p‐type Si solar cells has been measured and discussed. Subsequently, an exponential decay fit of the loss in cell efficiency is applied in order to estimate the difference in the energy output for both cell types in three different territories: Belgium (EU), Seattle and Austin (US). The observed trends in the difference in energy output between both cells, as a function of time of the year and region, are as expected and discussed. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)