Some sun helps :) but the SolarCity tiles use silicon PV......

Some sun helps but the SolarCity tiles use silicon PV... where I think the angle of incidence of the light also plays a bigger part in the performance of the panels. Whereas with perovskite and DSC I think they make power from dawn to dusk without the need for direct strong sunlight and work better in overcast conditions so that could be a big plus for perovskite solar on steel.