Hierarchical self-assembled Cu2S nanostructures: Fast and reproducible spray deposition of effective counter electrodes for high efficiency quantum dot solar cells

The availability of a well-established procedure for fabricating reliable and reproducible counter electrodes for quantum dot sensitized solar cells is currently an issue, limiting both the functional performances of these devices and the possibility to compare results obtained in different laboratories. We present here a simple, cheap and fast method for Cu2S counter electrodes fabrication based on spray pyrolysis deposition. Application of prepared counter electrodes to SILAR-sensitized quantum dot solar cells results in high performance devices (photoconversion efficiencies as high as 3.75% and impressive incident photon-to-current- efficient higher than 90%) as well in excellent reproducibility.