Macroporous Silicon as a Model for Silicon Wire Array Solar Cells

TLDR: In this article, the authors investigated the behavior of macroporous silicon samples in photoelectrochemical cells, and their behavior has been compared to that of conventional, planar, Si/liquid junctions.

Abstract: Macroporous silicon samples have been investigated in photoelectrochemical cells, and their behavior has been compared to that of conventional, planar, Si/liquid junctions. The liquid electrolyte junction provided a conformal contact to the macroporous Si and allowed assessment of the trade-offs between increased surface area and decreased carrier collection distances in such systems relative to the behavior of planar semiconductor/liquid photoelectrochemical junctions. The electrolyte contained the dimethylferrocene/dimethylferrocenium redox system in methanol because this system has been shown previously to produce bulk recombination-diffusion-limited contacts at planar Si(100) electrodes under 100 mW cm-2 of simulated air mass 1.5 illumination. Introduction of a network of ∼2−3 μm diameter, ∼80 μm long pores into the Si was found to slightly reduce the short-circuit photocurrent density and the open-circuit voltage of the system, but energy-conversion efficiencies in excess of 10% were nevertheless obt...