Improved light absorbance and quantum-dot loading by macroporous TiO2 photoanode for PbS quantum-dot-sensitized solar cells

Macroporous titanium dioxide (TiO2) layer was formed through selective etching of silica (SiO2) microspheres incorporated in TiO2/SiO2 composite layer, resulting in a significant increase in the photovoltaic performance of PbS quantum-dot-sensitized solar cells (Q)DSSCs). Strategic incorporation of macroporous TiO2 layer on top of a mesoporous layer improved the light absorption characteristics, which is concurrently attributed to light scattering behaviour of macropores and increased loading of quantum dots (QDs) via successive ionic layer adsorption and reaction process. Thereby, a direct increase in the photocurrent density of PbS-QDSSC was ensued. Open-circuit voltage decay analysis combined with in-depth electrochemical impedance spectroscopy revealed a significant improvement in the electron life time and recombination resistance of QDSSC which was credited to the barrier effect of more uniformly loaded PbS QDs inside macroporous TiO2 photoanode. (C) 2017 Elsevier B.V. All rights reserved.