Carbon nanotubes/PANI composite as an efficient counter electrode material for dye sensitized solar cell

Abstract

Counter electrodes of dye sensitized solar cells (DSSCs) mainly employed platinum (Pt) as a catalyst due to high catalytic activity toward triiodide reduction in their operating process. However, using Pt in DSSCs highly increases the cost, which became a challenge for practical applications from their economic feasibility point of view. Therefore, in this work, we have developed a cost-effective material carbon nanotubes (CNTs) to replace expensive Pt. CNTs based DSSC has been considered as a potential candidate for future practical applications. We prepared CNTs/Polyaniline (PANI) composite as a CE material for DSSCs by doctor blade technique. The DSSCs fabricated with CNTs-PANI composite CE show the best power conversion efficiency (PCE) of 6.67%, which is comparable to 7.70% of Pt CE. The modified CNTs-PANI counter electrode exhibited excellent electrocatalytic activity that facilitated higher electron transfer, suppressed charge recombination, enhanced electron life, and faster triiodide reduction are confirmed by several characterisation techniques such as impedance spectroscopy, cyclic voltammetry (CV), and tafel analysis. A comparative study of these electrodes reveal that effective surface roughness plays an essential role in improving the electrochemical properties of the devices.