The role of copper in bifacial CdTe based solar cells

摘要

We present an innovative back contact for CdTe solar cell by the applicationudof a transparent conducting oxide, typically ITO, as a back electrical contact onudCdTe/CdS photovoltaic devices that acts as a free-Cu stable back contact and at the sameudtime allows to realize bifacial CdTe solar cells, which can be illuminated from either orudboth sides. The controlled insertion of a very limited amount of copper into the ITO backudcontact permits to have reproducible devices with high efficiencies still keeping theudbifacial configuration. Thin CdTe layer solar cells with ITO back contact have beenudrealized with efficiencies exceeding 10%, the reduced thickness of CdTe allows to have audbetter performance on the back-side illumination and reduces the amount of CdTeudmaterial.