Titanium Nitride Nanoflower Buds as Pt-Free Counter Electrodes for Dye-Sensitized Solar Cells
Subashini Gnanasekar, Andrews Nirmala Grace
Abstract
The nanostructure of titanium nitride was synthesized and investigated as a counter electrode (CE) to replace the conventional platinum CE for dye-sensitized solar cells (DSSCs). Titanium nitride nanoflower buds (TiN NFBs) were successfully prepared by a simple and efficient method of ammonialization of hydrothermally prepared titanium dioxide nanobuds with mixed anatase and rutile phase. Titanium nitride, with its unique nanostructure, exhibits good surface property with a wide range of porosity distribution, which is attributed to the possible electrocatalytic active sites. The electrochemical studies performed show that TiN NFBs demonstrate high electrocatalytic activity toward the iodide/triiodide electrolyte and exhibit good charge transfer kinetics with low charge transfer resistance comparable to the performance of the platinum electrode. The photocurrent voltage characteristics of the TiN NFB CE assembled DSSC shows that it achieves a power conversion efficiency (PCE) of 7.0%, which is very close to the PCE reached for the Pt CE based DSSC (7.4%). The 30 day stability study reveals the highly stable performance of the TiN NFB CE based DSSC and good corrosion resistance toward the iodide/triiodide redox electrolyte. Thus, the overall performance of the TiN NFB encourages further research to prepare different TiN nanostructures to replace the conventional costly Pt CE for large area DSSCs to reach the consumer market.