Facile Synthesis of a Multifunctional SnO2 Nanoparticles/Nanosheets Composite for Dye-Sensitized Solar Cells.

Synthesizing SnO2 composite nanostructures via a facile one-step method has been proven to be a great challenge. By adjusting operating variables, such as the reaction solution's pH and solvent type, several SnO2 nanostructures, in particular, a function-matching SnO2 hybrid structure composed of irregular zero-dimensional nanoparticles (NPs) and two-dimensional nanosheets (NSs), could be created. The as-prepared SnO2 composites were then characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), and diffuse reflectance spectroscopy (DRS) to determine their physical properties. Dye-sensitized solar cells (DSCs) constructed with the resultant multifunctional SnO2 NPs/NSs composite exhibited the highest overall power conversion efficiency (PCE) of 5.16% among all products with a corresponding short-circuit current density of 18.6 mA/cm2 and an open-circuit voltage of 0.626 V. The improved performance can be attributed to the combined effects of each component in the composite, i.e., the intentionally introduced nanosheets provide desired electron transport and enhanced light scattering capability, while the nanoparticles retain their large surface area for efficient dye absorption.

Self-Seeding Synthesis of Hierarchically Branched Rutile TiO2 for High-Efficiency Dye-Sensitized Solar Cells.

This study presents a unique and straightforward room temperature-based wet-chemical technique for the self-seeding preparation of three-dimensional (3D) hierarchically branched rutile TiO2, abbreviated HTs, employing titanate nanotubes as the precursor. In the course of the synthesis, spindle-like rutile TiO2 and the intermediate anatase phase were first obtained through a dissolution/precipitation/recrystallization process, with the former serving as the substrates and the latter as the nucleation precursor to growing the branches, which finally gave birth to the production of 3D HTs nanostructures. When the specifically created hierarchical TiO2 was used as the photoanode in dye-sensitized solar cells (DSCs), a significantly improved power conversion efficiency (PCE) of 8.32% was achieved, outperforming a typical TiO2 (P25) nanoparticle-based reference cell (η = 5.97%) under the same film thickness. The effective combination of robust light scattering, substantial dye loading, and fast electron transport for the HTs nanostructures is responsible for the remarkable performance.