A low cost carbon black/ polyaniline nanotube composite as efficient electro-catalyst for triiodide reduction in dye sensitized solar cells

摘要

AbstractThe cost of platinum (Pt) counter electrode (CE) accounts for over 40% of the total cost of a dye sensitized solar cell (DSSC), thus replacing Pt with a cheaper material can significantly reduce the overall cost of the device. To this end, a novel cost-effective mesoporous carbon black (CB)/polyaniline nanotube (PAniNT) nanocomposite was fabricated as a potential CE material. The nanocomposite, prepared by chemical oxidation polymerization of aniline in the presence of CB, was characterized by Fourier transform infra-red spectroscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Different amount of CB were added in the polymer matrix to optimize the electro-catalytic activity of the CB/PAniNT nanocomposite towards reduction of I3?to I?. Cyclic voltammetry, current density-voltage measurements, electrochemical impedance spectroscopy and Tafel plot analysis showed that incorporation of CB resulted in an augmented active catalytic surface area and enhanced charge transfer from CE to the electrolyte. These factors contributed towards achieving a high performance DSSC with efficiency of 6.62% in liquid electrolyte (LE) and 4.82% in polymethyl methacrylate based polymer gel electrolyte (PGE) under irradiation of light (100?mW?cm?2). Furthermore, the effect of CE thickness was also studied in detail and the cell performance was found to improve proportionally with growing thickness. An optimized device was finally assembled with a 10.58?μm thick 0.75?wt% CB/PAniNT nanocomposite film as CE corresponding to JSC, V0Cand RCTvalues of 12.52?mA?cm?2, 0.74?V and 0.99?Ω for LE, and 9.11?mA?cm?2, 0.74?V and 1.30?Ω for PGE respectively.Graphical abstractDisplay OmittedHighlights?A novel CB/PaniNT nanocomposite was synthesized and systematically investigated as counter electrode in DSSCs.?Superior catalytic property at par with Pt CE was observed by CV, EIS, JvsV characteristics.?Optimum photovoltaic performance was obtained when [I2]/[I?] ratio was 1:10.?Increasing thickness of the CE exerted a positive influence on the cell performance.?The nanocomposite CE worked effectively in both l