Performance optimization of dye-sensitized solar cells by gradient-ascent architecture of SiO2@Au@TiO2 microspheres embedded with Au nanoparticles

Abstract

Highly homogeneous, well dispersed SiO2@Au@TiO2 (SAT) microspheres decorated with Au nanoparticles (AuNPs) were prepared and incorporated into the photoanode with an optimized concentration gradient-ascent. The effects of SAT microspheres and the gradient-ascent architecture on the light absorption and the photoelectric conversion efficiency (PCE) of the dye-sensitized solar cells (DSSCs) were investigated. Studies indicate that the introduction of SAT microspheres and the gradient-ascent architecture in the photoanode significantly enhance the light scattering and harvesting capability of the photoanode. The DSSC with the optimized SAT gradient-ascent photoanode has the maximum short circuit current density (Jsc) of 17.7 mA cm−2 and PCE of 7.75%, remarkably higher than those of the conventional DSSC by 23.7% and 28.0%, respectively. This significantly enhancement of the performance of the DSSC can be attributed to the excellent light reflection/scattering of SAT, the localized surface plasma resonance (LSPR) effect of AuNPs within the microspheres, and the gradient-ascent architecture of SAT microspheres inside the photoanode. This study demonstrates that the tri-synergies of the scattering of SAT microspheres, the LSPR of AuNPs and the gradient-ascent architecture can effectively improve the PCE of DSSC.