Development of Graphene Nano‐Platelet Ink for High Voltage Flexible Dye Sensitized Solar Cells with Cobalt Complex Electrolytes

Graphene nanoparticles have been subject to intensive investigation as a replacement for platinum as the catalyst in dye sensitized solar cells (DSCs), but few of these investigations examine the application for flexible cells with deposition processes suitable for industrial fabrication. This work introduces a transparent water based graphene ink that can be dried rapidly at less than 110 ºC making it particularly suitable for roll to roll deposition on plastic substrates. This ink has application as a catalyst for dye sensitized solar cells utilizing cobalt complex electrolytes with efficiency of over 6 % and a Voc of 0.89 V at 1 sun demonstrated. A flexible DSC with a printed catalyst and cobalt redox mediator is reported, with efficiency of over 6.0 % and Voc of 0.6 V at 800 lux. This work develops a GNP ink of high surface area which can be printed using roll to roll technologies to produce a semi‐transparent catalyst. Post deposition the ink needs only a 110 °C drying step enabling the use of plastic substrates. Flexible dye sensitized solar cells suitable for indoor applications are produced with efficiencies of over 6.0%.