Electrochemical storage cell based on polycrystalline silicon. Final report, 1 March 1981-1 March 1982

Theoretical and experimental investigations on the performance of n and p-type silicon in solution for efficient solar energy conversion were conducted. Part of the work sought to identify redox couples capable of inducing maximum band bending (highest open circuit voltage) and limit the corrosion for both n and p-type silicon. High photovoltages were obtained by using vanadium (II/III) and ferrocene/ferricenium couples for p-type and n-type silicon respectively. These couples demonstrated reasonable stability, but their efficiency was limited by the growth of a relatively thick insulating SiO/sub 2/ corrosion layer. Corrosion studies were performed to evaluate the use of HF to remove the corrosion layer and to consider the interaction between HF and the redox couple. Much of the experimental and theoretical work focused on the effect of the surface oxide on solar cell characteristics and led to a variety of surface treatments aimed at improving the fill factor of silicon photoelectrochemical cells. The surface treatments included high temperature annealing of the normal oxide under an argon or hydrogen atmosphere, coating a p-n junction with a thin layer of platinum, and passivation with poly-vinylcarbazole polymer. (LEW)