Optical Characterization of Dye-Sensitised Tio2 Thin Films for Solar Cell Applications
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Date
2022
Authors
Kainyu, Kabuga Pauline
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
The use of dye-sensitized solar cells to harness solar energy has gained interest
because of their simplicity and are cheaper to manufacture. They can also be glazed
on flexible substrates for improved conversion efficiency. Standard DSSC consist of
materials made of transparent conducting oxides (TCOs) with titanium dioxide
(TiO2) used as semiconducting material. Synthetic dyes or natural dyes are utilized as
sensitizers to modify the TiO2 film. The goal of the current study was to find out the
potential of organic dyes from blue berry and spinach as sensitizing agents for TiO2
films by investigating their influence on optical properties of the films and energy
conversion efficiency of DSSC employing the said films. The blueberry and the
spinach dyes were extracted from blueberry fruit and spinach leaves respectively and
were taken into the nano-porous titania substrates. The nano-porous TiO2 paste was
sourced from Solaronics SA and its film generated on the glass surface by employing
screen printing technique. Ruthenium dye was used as a reference dye. Using
DUV3700 spectrophotometer the TiO2 film was characterized to obtain its optical
properties which were transmittance, reflectance and absorbance for both sensitized
and un-sensitized TiO2 films. The optical results showed blue berry sensitized TiO2
had low reflectance, transmittance and high absorbance compared to all other
samples both sensitized and un-sensitized. Spinach sensitized TiO2 films had high
reflectance, transmittance and low absorbance. On energy conversion efficiency, the
DSSC fabricated using Ruthenium dye had the highest efficiency of ~ 2%. The
DSSC fabricated with Blue berry dye followed closely at ~ 1.5 % efficiency while
the DSSC employing spinach dye had the lowest conversion efficiency of ~ 0.6 %.
Diluting the dyes with distilled water improved conversion efficiency for DSSCs
fabricated employing the blue berry and spinach dyes. From the study blue berry dye
has shown a more promising potential for fabrication of the DSSCs. However,
further study is required to optimize the concentration of the dyes as diluting the dyes
enhanced the performance of the dye as a DSSC sensitizer.
Description
A Thesis Submitted in Partial Fulfillment of the Requirements for the Award of the Degree of Master of Science (Material Science) in the School of Pure and Applied Sciences of Kenyatta University
Keywords
Optical, Characterization, Dye-Sensitised, Tio2, Thin Films, Solar Cell, Applications