CUINS2 WITH LAMELLAR MORPHOLOGY .1. EFFICIENT PHOTOANODES IN ACIDIC POLYIODIDE MEDIUM

CuInS2 grown in a steep temperature gradient acquires a peculiar lamellar morphology, similar to that of layered compound semiconductors. Thin electrodes (of thickness down to 30 to 40 mum) can be prepared by cleavage, reducing series resistance in the bulk of the semiconductor. The liquid junction of n-CuInS2 With acidic polyiodide medium (2M HI, 2.5M CaI2, 40 mM I2) was investigated. The best photoanodes attained quantum yields of monochromatic light of about 0.7 and conversion efficiencies above 7% under simulated AM1 sunlight. Their performance does not decrease substantially under moderately concentrated sunlight (300 to 400 mW cm-2), due to the small ohmic losses. Cell output appears quite stable during the first week of operation, but irregular electrode corrosion is observed, which may be detrimental to long term operation.