Click

on the excitation icon $($squiggly red arrow$)$ and select the ONE$-$SUN.EXC

file. Then run the simulation $($the running man icon$).$ At the bottom of the main screen, you can see the power output of more than

$2$ Watts over $100$cm$^2,$ which means the cell is

operating above

$20\%$ efficiency.

The bulk lifetime for electrons and holes is set to $5000$ microseconds. Keeping the values for both equal,

$(\backslash$tau n$=\backslash$tau p$),$

to what level $($in microseconds$)$ can the bulk lifetimes degrade before the cell efficiency drops to $18\%?$