Compression of ZnO nanoparticle films at elevated temperature for flexible dye-sensitized solar cells

This article presents the fabrication of flexible zinc oxide (ZnO) based dye-sensitized solar cells (DSSCs). To get homogeneous compact ZnO photoelectrode, we introduce a new post-treatment technique, namely hot-compress method (compression at elevated temperature). For further improvement, titanium oxide (TiO₂) nanoparticle at different percentage was added to the ZnO paste as a binder material. The performances of the cells were analyzed by i–v, UV–Vis NIR, external quantum efficiency (EQE), X-ray diffraction spectroscopy (XRD), and scanning electron microscopy (SEM) image. The result implies that the proposed hot-compress method gives homogenous compact ZnO layer, which enhances the photogenerated electron density of the device. The surface morphology and photovoltaic performance data of the DSSCs confirm that the hot-compress method is better than the other conventional post-treatments. The addition of TiO₂ with the ZnO paste as a binder material exhibited better adhesion as well as better photovoltaic performances compared to the DSSCs prepared by only ZnO. The highest power conversion efficiency (η) of 1.75% was obtained for the ZnO based cell prepared by the addition of 10% TiO₂ along with hot-compress as a post-treatment. This efficiency value was higher compared to the conventional post-treated ZnO based DSSCs. - Highlights: • Flexible ZnO base dye-sensitized solar cell was prepared successfully. • 120 MPa compression at 70 °C annealing was found as optimum post surface treatment. • 10% TiO₂ with ZnO enhanced the adhesion as well as photovoltaic performance. • Heat and compression was an effective way to fabricate low temperature flexible DSSC.