Bilayer film electrode of brookite TiO2 particles with different morphology to improve the performance of pure brookite-based dye-sensitized solar cells

摘要

A novel bilayer brookite TiO2 film photoanode consisting of quasi nanocube film as underlayer and rice like submicrometer particle film as overlayer are fabricated for improving the photovoltaic properties of the pure brookite-based dye-sensitized solar cells (DSSCs). The brookite TiO2 nanocubes have a mean size of similar to 50 nm, and the brookite TiO2 rice-like particles have diameter of similar to 600 nm and length of similar to 1100 nm. An optimal photovoltaic conversion efficiency of 5.51% is obtained from the bilayer brookite-based solar cell, with similar to 41% improvement in the efficiency as compared to the single brookite nanocube film-based one (3.91%) under AM 1.5G one sun irradiation. The bilayer brookite-based solar cell shows not only reduced charge recombination and dark current, but also prolonged electron lifetime compared to the single brookite nanocube film-based one. All these lead to a higher photocurrent and voltage, and then to the improved efficiency of the brookite-based solar cell. The present results demonstrate a clear advance towards efficient improvement of the photovoltaic performance of pure brookite-based solar cells. (C) 2016 Elsevier B.V. All rights reserved.