Abstract:
This work reports the multifunctionality of a novel Ru based dye (RuC) in enhancing the
performance of nanocrystalline Titanium dioxide (TiO2) / Poly (3-hexylthiophene) (P3HT) hybrid solar cells.
TiO2 / P3HT nanocomposite films were fabricated with and without the RuC dye as the interface modifier
and their optical properties were tested using UV-Vis and photoluminescence (PL) spectroscopies. UV-Vis
spectra of TiO2 / RuC and TiO2/RuC/P3HT films ensure that the absorption spectra is broadened in the UV
region due to the addition of the RuC dye. The PL measurements were carried out by pumping with laser
at wavelength corresponds to maximum absorption of P3HT. The PL of TiO2 / P3HT nanocomposite films
were significantly quenched when the RuC dye was introduced at the TiO2 / RuC interface. The PL
quenching ensure the efficient exciton dissociation in P3HT when RuC is introduced. The corresponding
solar cells were then fabricated using successive evaporation of MoO3 and silver on top of the films and
characterised under monochromatic and under Air Mass (AM) 1.5 conditions (100 mW cm−2
, 1 sun). The
insertion of the RuC dye suppresses the dark current while extends external quantum efficiency spectra.
As such, device with dye shows improved open circuit voltage and more than a factor of two times higher
short circuit current density in comparison with the corresponding control. Hence, RuC dye improves the
power conversion efficiency by a factor of two. This study concludes that, RuC dye has dual role; extending
the spectral response and suppressing the dark current.
