Dear Pradeep,

The idea of a solar panels are to trap maximum amount of solar light or heat.But with spinning conical cells,the time for which the cell is exposed to sinlight is less so the amount of electricity from each cell will be less and so the cell may not be used for its maximum efficiency

Dear Poornima

In my view, it's not the time it is exposed to sunlight matters where us total irradiance matters..Even though it is exposed for longer time the efficiency will reduce after a threshold level.