Properties of the Pt counter electrode using microwave employed dye sensitized solar cells

The energy conversion efficiency (ECE) of the Pt counter electrode (CE) was improved by microwave irradiation for 0-40 seconds. A 0.45 cm² sized device with a glass/FTO/blocking layer/TiO₂/Vdye/electrolyte/microwave-100 nm Pt/glass was prepared. The photovoltaic properties, such as the short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), and energy conversion efficiency (ECE), were characterized using a solar simulator and potentiostat. The stress of the Pt layer was examined by X-ray diffraction. The interfacial resistance and catalytic activity were examined by impedance and cyclic voltammetry. The change in surface roughness was examined by atomic force microscopy. The 100 nm Pt CE after microwave irradiation for 10 seconds showed a large compressive stress of over -4.43×10^-3. The measured energy conversion efficiencies of the dye-sensitized solar cell devices with the Pt only and microwave Pt (10 seconds) counter electrodes were 4.60% and 5.72%, respectively. As the microwave irradiation time was increased to more than 10 seconds, the ECE decreased to that of the as-deposited Pt CE due to a decrease in the surface area of the Pt layers. These results suggest that the use of a Pt catalytic layer with the appropriate microwave irradiation conditions may improve the efficiency of dye-sensitized solar cells.