Synthesis and analysis of electrospun TiO2 nanofiber incorporated with nanoscale inclusions for improved DSSC efficiency
The manufacturing, performance and properties of dye sensitized solar cells (DSSC) have been researched for some time and there have been many new techniques and methods that have been developed to improve the efficiency of solar cells. This research paper describes in detail about a new technique in the manufacturing of the DSSC. The method involves introduction of graphene and C60 in the TiO2 nanofibers. Graphene and C60 have high electrical conductivity and low resistance. Graphene is a form of carbon, in which the carbon atoms are arranged in a regular hexagonal pattern in a plane. The thickness of a graphene sheet is equivalent to the thickness of one carbon atom. C60, also known as Fullerene, is a formation of 60 carbon atoms in soccer ball shape. The TiO2 nanofibers are created by using an electrospinning method which creates long strands with diameters of 100 to 200 nm. The graphene and C60 nanoparticles are incorporated in the nanofiber with varying percentages of 1%, 2%, 4%, and 8%. The nanofibers are then mixed in a solution to form a paste which is then applied on a conductive glass by using a doctor blading technique. This technique enables to create solar cells with variable thicknesses of 7μm to 45μm. With these experiments the effects of the manufacturing technique, thickness of the paste, different percentages of Graphene or C60 on overall efficiency of the solar cell were studied. This paper also includes the TiCl4 treatment which greatly increases the efficiency of DSSC. During the manufacturing of the solar cells the antireflective coating was not used, as the main objectives were to observe the effects of the electro-spinning process and how it affects the efficiency of the dye sensitized solar cell. The incorporation of graphene and C60 in the TiO2 nanofibers was shown to increase the efficiency, compared to the TiO2 nanofibers alone. The general efficiency for graphene and C60 are in the range of 4.3% to 5.6%. Data sets were created with minimum of 3 and maximum of 6 samples. Each data set corresponded to a given set of parameters that were held constant for that set. Appendix includes the data set for current density versus voltage graphs of data set. Box and whisker plots show the spread of data and few outliers in the sample testing. Fill factors shows a trend for graphene and C60 in the test samples. Overall, the present study may open up new possibilities of using these inclusions in various energy systems for improved efficiencies.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering