Abstract:
This work focuses on the role of Lithium doped Poly(3-hexylthiophene)(P3HT) in metal-free
quaterthiophene (4T) dye treated Titanium dioxide (
TiO2) based hybrid solar cells. The dye treated
hybrid solar cells with Lithium doped P3HT showed efficiencies (3.95%) of nearly a factor of four times
higher than the pristine P3HT based control TiO2/
4T/P3HT devices (1.04%). The enhancement of the
efficiency is mainly due to highly efficient charge collection attributed to enhanced charge transport
and light harvesting properties of Lithium doped P3HT polymer. The optimized solar cells with Lithium
doped P3HT showed a high short circuit current density over 13 mA/cm2, under simulated irradiation
of intensity 100 mW/cm2 with AM 1.5 filter. This significant increase in current density in TiO2/
4T/
doped P3HT solar cell is also confirmed by both the broadened External Quantum Efficiency spectrum
and significant photoluminescence quenching upon replacement of pristine P3HT with doped P3HT
on 4T dye treated TiO2
electrode. With Lithium doped Spiro-OMeTAD instead of Lithium doped P3HT,
similar devices showed efficiencies over 3.30% under simulated irradiation of 100 mW/cm2 with AM 1.5
filter.
