Highly efficient dye-sensitized solar cell with an electrostatic spray deposited upright-standing boron-doped ZnO (BZO) nanoporous nanosheet-based photoanode

Abstract

Electrostatic spray deposition for the fabrication of well cross-linked upright-standing boron-doped ZnO (BZO) nanoporous nanosheets and their applications in dye-sensitized solar cells (DSSCs) are investigated with the aim of developing cost-effective alternative fabrication methods and improving the ZnO-based DSSCs performance. The highest solar-to-electric energy conversion efficiency of 6.75% is obtained by using the well cross-linked upright-standing BZO nanoporous nanosheets. This efficiency is significantly improved over the 3.0% achieved for BZO films only including nanosized crystallites and also higher than the 2.62% for un-doped ZnO nanosheets. The influence of the sputtering time of platinum (Pt) on the photovoltaic performance of the DSSC is also investigated. The fabricated cells exhibited highly durable cell performances, even after one month under atmospheric conditions. The efficiency achieved for the best DSSC in this work is the highest ever reported value for a ZnO nanoporous nanosheets-based DSSC. The performance enhancement of the BZO cells can be reasonably inferred to arise from the intrinsic components of the films, as well as the sunlight harvesting and photon-to-electron transfer process of the cells. In addition, the photocurrent density of our BZO-based cell is now comparable to that of the TiO₂-based cells, and its conversion efficiency has reached more than half of the highest value (11.18%) recorded with the TiO₂ electrode.