Opaque Pt counter electrodes for dye‐sensitized solar cells

An opaque platinum (Pt) film is deposited via the chemical bath method on an FTO substrate and assigned as a counter electrode (CE) of dye-sensitized solar cells (DSSCs). Optical properties opaque Pt film indicates the enhanced reflectivity compared to a conventional transparent Pt CE deposited by a spin coating method. The electrochemical impedance spectroscopy manifests the opaque Pt CE has a smaller series and charge-transfer resistances than that of transparent Pt. Tafel and cyclic voltammetry results verify the superiority of opaque Pt CE considering excellent electrocatalytic activity toward redox couple. A mechanical stability test affirms the excellent adhesion properties of the opaque Pt CE on FTO substrates. As a consequence, DSSC having the opaque Pt CE delivers a high electrical power conversion efficiency of 5.06%, outperforming the cell with the transparent Pt CE (4.31%) under the same conditions. Prospectively, the design of a device with an opaque Pt CE can be extended to other optoelectronic applications, opening up the opportunities for a host of high-performance devices.