The influence of morphology of hematite (α-Fe2O3) counter electrodes on the efficiency of dye-sensitized solar cells

Abstract

The performance of dye-sensitized solar cells (DSSCs) is much related to their counter electrode (CE) behavior. It is well known that the performance of DSSCs depends on the morphology of counter electrodes. Hematite (α-Fe2O3) with different morphologies such as nanoparticles (NP), nanofibers, nanoflowers and nanorods was successfully fabricated via hydrothermal reactions and introduced into DSSCs as a CE. The characteristic behavior of α-Fe2O3 micro/nanostructures were investigated by X-ray diffraction and scanning electron microscopy. The photovoltaic performance of DSSCs and electrochemical catalytic activity of nanostructures were compared. Cyclic voltammetry curves have indicated that NP counter electrodes exhibit a higher electro catalytic activity for iodide (3I−)/tri-iodide (I3-) redox reaction as compared to other morphologies. This supremacy may be attributed to the larger surface area of nanoparticles and their crystal structure which has grown in [012] and [104] directions. A maximum efficiency of 4.60% was obtained for cells using NP in a CE. In this paper, α-Fe2O3 is introduced as a promising substitute material for the expensive Pt CE in low-cost DSSCs.