Nanoparticle-Based Contacts to CdTe

Our team has been investigating the use of particle-based contacts in CdTe solar cell technologies. Toward this end, particles of Cu-doped HgTe (Hg-Cu-Te) and Sb-Te have been applied as contacts to CdTe/CdS/SnO2 heterostructures. These metal telluride materials were characterized by standard methods. Hg-Cu-Te particles in graphite electrodag contacts produced CdTe solar cells with efficienciesabove 12% and series resistance (Rse) of 6 ohms or less. Metathesis preparation of Cu(I) and Cu(II) tellurides were attempted as a means of characterizing the valence state of Cu in the Hg-Cu-Te ink. For Sb-Te contacts to CdTe, open circuit voltages in excess of 800 mV were observed, however, efficiencies were limited to 9%; perhaps a consequence of the marked increase in the Rse in thesenon-graphite containing contacts. Aceylene black was mixed into the methanolic Sb-Te colloid as a means of reducing Rse, however, no improvement in device properties was observed.