Question to Solar Cell Manufacturers

Dear Manufacturers,

there is something I do not fully understand:

While commercial Solar Cells have an Efficiency of about 15-18 %, it is claimed that under perfect lab conditions 50 % are achievable…

“under perfect Lab conditions means … “much more expensive techniques/materials”??

As far as I know the sun does now shine in Labs?

So what is the problem?

can please somebody shed some light on this ?

Thank you

Daniel

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