CdTe solar cells with a PCBM back contact

PCBM is evaluated as a primary contact to CdTe due to its high valence band energy. PCBM films were characterized in terms of morphology, area coverage, thickness, electrical and optical properties, and used as a back contact for CdTe solar cells. PCBM solutions were developed by mixing PCBM with chloroform (CFM) and ethylenediamine (EDA) and deposited via spin coating. The performance of devices with PCBM:CFM and PCBM:EDA back contacts are compared to those with baseline CdTe devices with a Cu2Te/Ni contact. For PCBM cells, the back contact properties were varied with subsequent anneals of 60 °C, 180 °C, and 240 °C. The device performance however was low as J-V results reveal a blocking contact.