Nanostructured platinum counter electrodes by self-assembled nanospheres for dye-sensitized solar cells

Abstract

We report a method to fabricate nanostructured Pt counter electrodes for DSSCs using self-assembly nanosphere monolayers. The spin-coating in combination with the water transfer technique was adopted to produce low-defect, large-area and close-packed (hexagonal) self-assembly nanosphere monolayers on glass substrates. By vacuum deposition of SiO2 through pores of self-assembly nanosphere monolayers, arrays of SiO2 nanodots were formed on glass substrates. Further blanket deposition of Pt on such nanostructured substrates gave nanostructured Pt counter electrodes for DSSCs. DSSCs using such nanostructured Pt electrodes showed enhanced short-circuit currents, spectral responses, and power conversion efficiencies, compared to DSSCs using unstructured Pt counter electrodes. Investigations by electrochemical impedance spectroscopy revealed the reduction of charge-transfer resistances for the Pt/electrolyte interface in using nanostructured Pt counter electrodes, due to increase of the active surface areas and thus the electro-catalytic ability (activity).