ZnO solid-state dye sensitized solar cells using composite electrolyte of poly(3-hexylthiophene-2,5-diyl) and carbon nanotubes

Abstract

Solid-state dye sensitized solar cells (DSSCs) could become alternative to liquid electrolyte-based cells which suffer from several problems such as leakage, encapsulation, and cell interconnections within the module. In this paper we focus on ZnO solid-state DSSCs employing thiophene-based polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) as hole conducting agent. The effect of the addition of multiwalled carbon nanotubes (MWCNTs) in P3HT on the solar cell parameters was investigated. Current-voltage (I-V) characteristics of the different cells were obtained having different wt % of MWCNTs. Using the I-V characteristics and single diode model for the solar cell, various parameters such as the photocurrent, the saturation current of the diode, the series resistance, the shunt resistance, and the ideality factor were determined. The use of MWCNTs with polymer P3HT increased the photovoltaic performance of the solar cells. Highest device performance was achieved with 0.8 wt % of MWCNTs in P3HT. The role of MWCNTs for efficient hole transfer was discussed in terms of series and shunt resistances.