Hierarchical SnO2 microspheres prepared by hydrothermal process for efficient improvement of dye-sensitized solar cell properties

In the present investigation, hierarchical SnO 2 microspheres were synthesized by controlled hydrothermal technique. The reaction temperature was kept fixed, while the reaction processing time varied from 16 to 24 h. Microscopic studies revealed these hierarchical microspheres composed of nanoparticles. The hydrothermal process time strongly influences the surface morphology of the sample deposited for 16 h by hydrothermal processes having dense microspherical morphology of agglomerated nanoparticles with 20 nm diameter. While, the sample deposited for 24 h shows well-grown microspheres with well-dispersed nanoparticles having 20 nm due to surface etching. On the basis of experimental results, a possible growth mechanism for the formation of the SnO 2 hierarchical nanostructure was speculated. The well-dispersed nanoparticulate microspheres deposited for 24 h provide high surface area (29.56 m 2 g −1 ) which facilitates effective light scattering. The dye-sensitized solar cell properties show that 1.68 and 3.12 % power conversion efficiency for the samples deposited for 16 and 24 h, respectively. Graphical Abstract