Improved photovoltaic performance of dye-sensitized solar cells with modified self-assembling highly ordered mesoporous TiO2 photoanodes

Abstract

Strategies for improving the photovoltaic performance of dye-sensitized solar cells (DSSCs) are proposed by modifying highly transparent and highly ordered multilayer mesoporous TiO2 photoanodes through nitrogen-doping and top-coating with a light-scattering layer. The mesoporous TiO2 photoanodes were fabricated by an evaporation-induced self-assembly method. In regard to the modification methods, the lightscattering layer as a top-coating was proved to be superior to nitrogen-doping in enhancing not only the power conversion efficiency but also the fill factor of DSSCs. The optimized bifunctional photoanode consisted of a 30-layer mesoporous TiO2 thin film (4.15 mm) and a Degussa P25 light-scattering top-layer (4 mm), which gives rise to a similar to 200% higher cell efficiency than for unmodified cells and a fill factor of 0.72. These advantages are attributed to its higher dye adsorption, better light scattering, and faster photon-electron transport. Such a photoanode configuration provides an efficient way to enhance the energy conversion efficiency of DSSCs. Journal Name Strategies for improving the photovoltaic performance of dye-sensitized solar cells (DSSCs) are proposed by modifying highly-transparent and highly-ordered multilayer mesoporous TiO 2 photoanodes through nitrogen-doping and top-coating with a light-scattering layer. The mesoporous TiO 2 photoanodes were fabricated by an evaporation-induced self-assembly method. In regard to the modification methods, the light-scattering layer as a top-coating was proved to be superior to nitrogen-doping in enhancing not only 10 the power conversion efficiency, but also the fill factor of DSSCs. The optimized bifunctional photoanode consisted of a 30-layer mesoporous TiO 2 thin film (4.15 m) and a Degussa P25 light-scattering top-layer (4 m), which gives rise to a ~200% higher cell efficiency than for unmodified cells and a fill factor of 0.72. These advantages are attributed to its higher dye adsorption, better light scattering, and faster photon/electron transport. Such a photoanode configuration provides an efficient way to enhance the 15 energy conversion efficiency of DSSCs.

Architecture designed ZnO hollow microspheres with wide-range visible-light photoresponses

“…These multiple optical effects have been successfully employed to enhance the visible-light harvesting capability of solar energy harvesting devices. [29][30][31] It is interesting that the visible light absorption of the ZnO hollow microspheres has strong correlation with the size of the constituent nanostructured aggregates. In detail, the visible light absorption centre of the hollow microspheres shied from 400 nm to 450 nm and then to around 510 nm, with the variation of the constituent nano-units from nanowire network ($200 nm), to mesoporous nanoballs ($200 nm), and then to nanosheet stacks (250-300 nm in width).…”

Strategies for designing metal oxide nanostructures

“…5d (bottom) presents the mesoporous TiO2 nanospindles synthesized with the assistance of CTAB surfactants [199]. Sun et al [221] fabricated mesoporous TiO2 thin films by using either Pluronic P123 or Pluronic F127 surfactant (PEO106PPO70PEO106, Mw = 12,600 g mol −1 ). The mesoporous thin films with channels 10-13 nm in diameter have been demonstrated to be helpful to improve the solar energy conversion efficiency.…”

“…The synthesis of 3D nanostructures with complex configurations, for examples, 3D dendritic microspheres with fine constituent nanostructures, mesoporous structures, and hollow microspheres with controlled constituent nanostructures, is possible with the help of surfactants and hard templates [219][220][221]. Fig.…”

Two-step self-assembly of hierarchically-ordered nanostructures

“…44 Surfactants have been widely used as soft templates and morphology controlling agents to fabricate desired nanostructures. [45][46][47] Surfactant-directed synthesis can help to prepare monodisperse samples with narrow size distributions, low tendency towards agglomeration, excellent control over crystal size, good control over crystal shape, and good redispersibility. 48,49 In this concept paper, the molecular selfassembly involved in the two-step self-assembly is mainly surfactant-assisted self-assembly.…”