1 research outputs found
Adjustment of Conduction Band Edge of Compact TiO<sub>2</sub> Layer in Perovskite Solar Cells Through TiCl<sub>4</sub> Treatment
Perovskite
solar cells (PSCs) without a mesoporous TiO<sub>2</sub> layer, that
is, planar-type PSCs exhibit poorer cell performance as compared to
PSCs with a porous TiO<sub>2</sub> layer, owing to inefficient electron
transfer from the perovskite layer to the compact TiO<sub>2</sub> layer
in the former case. The matching of the conduction band levels of
perovskite and the compact TiO<sub>2</sub> layer is thus essential
for enhancing PSC performance. In this study, we demonstrate the shifting
of the conduction band edge (CBE) of the compact TiO<sub>2</sub> layer
through a TiCl<sub>4</sub> treatment, with the aim of improving PSC
performance. The CBE of the compact TiO<sub>2</sub> layer was shifted
to a higher level through the TiCl<sub>4</sub> treatment and then
shifted in the opposite direction, that is, to a lower level, through
a subsequent heat treatment. These shifts in the CBE were reflected
in the PSC performance. The TiCl<sub>4</sub>-treated PSC showed an
increase in the open-circuit voltage of more than 150 mV, as well
as a decrease of 100 mV after being heated at 450 °C. On the
other hand, the short-circuit current decreased after the treatment
but increased after heating at temperatures higher than 300 °C.
The treated PSC subjected to subsequent heating at 300 °C exhibited
the best performance, with the power conversion efficiency of the
PSC being 17% under optimized conditions