Abstract:
There is sustained attention to achieve high energy conversion in dye-sensitized solar
cells (DSCs), as they exhibit the potential to overcome some of the pitfalls of
conventional solar cells. Systematically arranged multi-layers of TiO2 nanoparticles
prepared to enhance light-harvesting efficiency and electron transport across the
photoanode are suitable to make highly efficient DSCs. Further, the power conversion
efficiencies of DSCs can be improved by employing binary iodides in the gel polymer
electrolyte. In present work, photoanodes stacked to 1–6 layers are combined with gel
electrolyte based on Poly(ethylene oxide) having LiI and tetrahexylammonium iodide
(Hex4NI) binary salts with the ratio of 2:3. The first two layers and 3rd layer of the
photoanode are prepared by spin coating dispersions of TiO2 nanoparticle of the size 13
and 21 nm respectively on the conducting glass substrate of fluorine-doped tin oxide. For
the preparation of 4th, 5th, and 6th layers polyethylene glycol and Triton X 100 are also
combined with TiO2 nanoparticle dispersion of the size 21 nm before the spin coating.
DSCs were assembled by sandwiching gel electrolyte between N719 dye-sensitized TiO2
photoanodes consisting of 1-6 layers separately and Pt counter electrodes. The DSC with
photoanode having five layers of TiO2 nanoparticles exhibits Jsc of 12.55 mA cm-2
, VOC
of 698 mV, and efficiency of 5.45% under the irradiation of 1000 W m-2
. The active area
of the cell was 0.19 cm2
. Hence, this study reports a reliable and simple fabrication
method to augment solar cell efficiencies by merging the positive effects of multilayered
TiO2 photoanode with well-ordered thicknesses and quasi solid-state gel polymer
electrolytes with mixed salt system.
Keywords: Dye-sensitized solar cells, Binary iodides, Gel polymer electrolyte, Spin
coating, Multilayered photoanode
