Broadband light confinement using a hierarchically structured TiO2 multi-layer for dye-sensitized solar cells

Abstract

Herein, we present a simple strategy for broadband light confinement without sacrificing dye-loading capacity by suitably combining multi-layer architecture with hierarchically structured TiO 2 . For this purpose, three distinct TiO 2 hierarchical nanomaterials were exploited to simultaneously realize high internal surface area and a graded series of optical properties (in terms of reflectance and transmittance). The present hierarchically structured multi-layer showed a remarkable improvement in the overall efficiency for dye-sensitized solar cells (DSCs): a maximum of 11.43% at 1 Sun (12.16% at 1/8 Sun) versus 8.15% at 1 Sun (8.26% at 1/8 Sun) for the reference cell made of a nanocrystalline TiO 2 single-layer. This notable result is attributed to the synergetic effects of the enhanced broadband light confinement, dye-loading, and charge-collection efficiency.

Design of multi-layered TiO2 nanotube/nanoparticle hybrid structure for enhanced efficiency in dye-sensitized solar cells

“…2b and Table 1. In our work, the optimum thickness of the TiO 2 NP reference photoanode was about 15 m (NP15), better than a thicker NP layer of 19 m (NP19), which is consistent with the previous results (about 12~15 μm) for high efficiency DSSCs [19,30]. The NP15 cell shows efficiency (η) of 4.71%, with the J SC of 10.20 mAcm -2 and V OC of 0.703 mV.…”

“…TiO 2 photoanode simultaneously possessing large surface area for dye-loading, superior electron transport and excellent light scattering is always sought after during the development of high performance DSSCs. Nanostructured multi-layered photoanodes have been constructed for high efficiency DSSCs, by combining nanorods or nanoparticles of various sizes with conventional NPs [18][19]. It is clear that the development of such hierarchical photoanodes which combines the advantages of the 1D nanomaterial and the conventional NPs would lead to both the efficient charge transport and the superior dye adsorption.…”

TiO2 nanotube structures for the enhancement of photon utilization in sensitized solar cells

“…For example, TiO 2 NTs feature excellent electron recombination and collection properties but suffer from insufficient internal surface areas for dye adsorption, while TiO 2 NPs show the opposite characteristics. To realize photoanodes with these multi-functions simultaneously to promote solar cell performances, multi-layered (two, three or more layers) structures can be designed, in which nanostructures of various morphologies and sizes are combined together in series, and each layer plays different roles in photon to electron conversion processes, including sufficient dye adsorption, fast electron diffusion and proper light recycling [98,[171][172][173][174][175][176].…”

“…Meanwhile, the additional light scattering component with high diffuse reflectivity is also commonly added, forming the hybrid structures. The scattering appears as a wide-band effect which enhances light absorption and quantum efficiencies in the entire visible region [98]. The typical structure of solar cell photoanodes based on double-layered nanocrystalline TiO 2 films is as follows: a transparent layer that adsorbs light-harvesting dye molecules, and a non-transparent scattering layer deposited on top of the transparent layer.…”

A novel glowing electrolyte based on perylene accompany with spectrum compensation function for efficient dye sensitized solar cells

“…To extend light harvesting and improve the PCE, efforts to improve the molar extinction coefficient of various dyes have been made [6,7]. Nevertheless, synthesis of a new dye or modification of an existing dye may come up with new problem, like the dyes of compatibility with the organic solvents or TiO 2 nanoparticles [6,8e10].…”