Influence of the silicon surface treatment on the properties of SiNWs/PVK hybrid solar cells

In this work, we have studied hybrid solar cells based on the polymer, poly (N-vinylcarbazole) (PVK) and silicon nanowires (SiNWs). The nanowires were treated with a fluorhydric acid solution to eliminate the oxide overlayer. The photovoltaic parameters of a set of bulk heterojunction solar cells were determined by IV-characterization and their morphology was investigated by scanning electron microscopy (SEM). The hybrid layer of HF-treated SiNWs and PVK, results in cell performance improvement in respect to a reference cell based on the as produced SiNWs. The improved device photovoltaic performance can be attributed to the improvement of the nanoscale morphology which can strongly affect the transport pathways for free charges and to a more efficient charge transfers from the polymer to SiNWs after elimination of the oxide overlayer.