High efficient Pt counter electrode prepared by homogeneous deposition method for dye-sensitized solar cell

A combined urea-assisted HD–EG method is used for fabricating a Pt counter electrode for the DSSC. It gives better control over size and dispersion of Pt NPs generated compared to conventional methods with lower resistance and higher efficiency. [Display omitted] ► Homogeneous deposition (HD) and reduction by ethylene glycol (EG) were tested. ► A Pt counter electrode for DSSC was prepared by the combined HD–EG method. ► The HD–EG method demonstrates excellent control over size and dispersion of Pt NPs. ► The Pt reveals high electrochemical surface area and electrocatalytic reduction of I3-. ► The HD–EG will bring great impacts on the development of efficient electrocatalysts. Platinum counter electrodes in DSSC are generally prepared by thermal reduction method. Poor control over Pt particle size, agglomeration and bad adhesion to the transparent conducting substrate, are some of the shortcomings affecting overall efficiency of the cell. In order to achieve better dispersion and control over the particle size, we explored direct deposition of metal nanoparticles (NPs) from their precursor solution onto the FTO glass substrate by using a simple and effective urea-assisted homogenous deposition (HD) method. This method works at substantially lower temperature for hydrolysis of urea and uses mild reducing agent, ethylene glycol (EG), giving better control over particle size along with better adhesion and negligible agglomeration compared to the thermal reduction method. DSSC prepared from such Pt counter electrode exhibited much enhanced photovoltaic performance compared to ones prepared by thermal and EG reduction alone, with better light-to-electricity conversion efficiency of 9.34% under one sun illumination. This excellent conversion efficiency is attributed to the uniform dispersion and smaller size of the Pt NPs prepared by the novel, combined urea-assisted HD–EG synthesis method.