Graphene/titania (G/TiO2) nanocomposite photoanodes were fabricated
for CdS quantum dots sensitized solar cells (QDSSCs) applications.
The effect of G/TiO2 ratio (0, 0.1, 0.2, 0.5, and 1.0 wt.%) on the
photovoltaic performance of CdS QDSSCs was investigated. CdS
QDs were deposited onto G/TiO2 nanocomposite films by successive
ionic layer adsorption and reaction (SILAR) technique for six
cycles. The current density–voltage (J–V) characteristic curves of
the assembled solar cells were measured at AM1.5 simulated
sunlight. The optimal G/TiO2 ratio was 0.2 wt.% for photovoltaic
performance. CdS QDSSCs based on 0.2 wt.% G/TiO2 nanocomposite
photoanode achieve 32% increase in conversion efficiency (g)
compared with those based on plain TiO2 NPs photoanode. The
photovoltage–decay curves of the assembled cell were recorded.
The electron–hole back recombination rates decrease significantly
for CdS QDSSCs based on 0.2 wt.% ratio of G/TiO2 nanocomposite
photoanode. The lifetime constants (s) is much larger for CdS
QDSSCs based on 0.2 wt.% ratio of G/TiO2 nanocomposite photoanode
compared to those based on plain TiO2 NPs photoanodes.