Hybrid [formula omitted]-HgS nanoparticles and P3HT layers for solar cells applications

Abstract

The use of inorganic nanoparticles as electron acceptors in hybrid solar cells has been increased. Some advantages compared to electron acceptors based on organic materials, are better electron transfer and lower production costs. We report the synthesis of β-HgS nanoparticles by a combination of solution method using polyvinylpyrrolidone (PVP) as stabilizing agent, and hydrothermal treatment to diminish nanoparticles size and improve size distribution. The combination of a bottom-up and a top-down technique proved to be an appropriate method to obtain HgS nanoparticles with sizes in the order of the Bohr radius, essential for charge carrier generation in the solar cell. Additionally, PVP was replaced by hexadecanethiol (HDT). This exchange allowed the spin coating of a thin film of β-HgS dispersed in poly(3-hexylthiophene) (P3HT) onto a glass substrate. Characterizations showed that the HgS nanoparticles and the polymer were homogeneously mixed, but several aggregated HgS nanoparticles were still present. The lowering in the photoluminescence signal of the layer is an indicative of charge carrier transfer between the nanoparticles and P3HT. Our results are encouraging for the development of hybrid solar cells using β-HgS nanoparticles and P3HT. To our knowledge, these results are the first obtained for β-HgS nanoparticles, using a bottom-up/top-down approach. It is also the first time a nano-β-HgS/P3HT layer with promising properties as hybrid solar cell is reported.