Abstract: The invention discloses nanocrystalline (NC) FeS2 thin films as the back contact for CdTe solar cells. In one example, the FeS2 NC layer is prepared from a solution directly on the CdTe surface using spin-casting and chemical treatment at ambient temperature and pressure, without a thermal treatment step. Solar cells prepared by applying the NC FeS2 back contact onto CdTe yield efficiencies of about 95% to 100% that of standard Cu/Au back contact devices. In another example, FeS2 is interposed between Cu and Au to form a Cu/FeS2 NC/Au back contact configuration yielding an efficiency improvement of 5 to 9 percent higher than standard Cu/Au devices.

Abstract: A photovoltaic cell structure is disclosed that includes a back contact layer that includes single wall carbon nanotube elements. The single wall carbon nanotube (SWNT) back contact is in electrical communication with an adjacent semiconductor layer and provides a buffer characteristic that impedes elemental metal migration from the back contact into the semiconductor active layers. In one embodiment, the SWNT back contact includes a semiconductor characteristic and a buffer characteristic. In another embodiment, the SWNT back contact further includes a metallic characteristic.

Abstract: The invention discloses nanocrystalline (NC) FeS2 thin films as the back contact for CdTe solar cells. In one example, the FeS2 NC layer is prepared from a solution directly on the CdTe surface using spin-casting and chemical treatment at ambient temperature and pressure, without a thermal treatment step. Solar cells prepared by applying the NC FeS2 back contact onto CdTe yield efficiencies of about 95% to 100% that of standard Cu/Au back contact devices. In another example, FeS2 is interposed between Cu and Au to form a Cu/FeS2 NC/Au back contact configuration yielding an efficiency improvement of 5 to 9 percent higher than standard Cu/Au devices.

Abstract: A photovoltaic cell structure is disclosed that includes a back contact layer that includes single wall carbon nanotube elements. The single wall carbon nanotube (SWNT) back contact is in electrical communication with an adjacent semiconductor layer and provides a buffer characteristic that impedes elemental metal migration from the back contact into the semiconductor active layers. In one embodiment, the SWNT back contact includes a semiconductor characteristic and a buffer characteristic. In another embodiment, the SWNT back contact further includes a metallic characteristic.