Multi-layered architecture of electrodes containing uniform TiO2 aggregates layers for improving the light scattering efficiency of dye-sensitized solar cells

Abstract

This study comes up with a new architecture of multi-layered photoanode electrodes containing two thick layers (i.e., 6 lm) of nanocrystalline TiO 2 particles and two thin layers (i.e., 1 lm) of uniform TiO 2 aggregates, which are alternately deposited. The aggregates layers are deposited by a straightforward gel process, developed for the preparation of uniform and sponge-like light scattering layer for dye-sensitized solar cells (DSSCs) applications. The aggregates layers are composed of uniform spherical particles with average diameter of 2 lm, containing small nanoparticles with the average grain size of 20 nm. The nanocrystalline layers contain 20-nm-diameter TiO 2 nanoparticles. X-ray diffraction reveals that the nanocrystalline layers have a pure anatase phase, whereas the aggregates layers show a mixture of anatase and rutile phases. Diffuse reflectance spectroscopy demonstrates that the multi-layered electrode enjoys better light scattering ability than that of mono-layered electrode due to the incorporation of a thin light scattering layer into the nanocrystalline film. The multi-layered DSSC shows the highest power conversion efficiency of 7.69 % as a result of higher light harvesting and less recombination which is demonstrated by electrochemical impedance spectroscopy. From IPCE measurement, the external quantum efficiency of the multi-layered cell is equal 88 %, which is higher than that of mono-layered cell (i.e., 78 %).

Crossover from compact to branched films in electrodeposition with surface diffusion

“…The production of multifunctional films is possible, for instance, by controlled changes in the film structure and architecture [24]. In many cases, deposited films show different stacking layers with different porosities and thicknesses [25], whose different physical and/or chemical properties ensure multifunctional behavior. For example, regarding photovoltaic applications, a layer with large branches and reduced specific surface area ensures the light harvesting, while a layer with small branches enhances the specific surface and favors loading of large molecules (e. g. dyes).…”

Improved Performance of Dye-Sensitized Solar Cells with TiO2 Nanoparticles/Zn-Doped TiO2 Hollow Fiber Photoanodes

“…This advantage of TiO 2 is attributed to its high photovoltaic performance in the visible region [14] and its ability to maximize the absorption of the dye sensitizer on the surface [18,19]. Extensive efforts have been undertaken to modify the morphology and structure of the semiconductor layer in the DSSC photoanode in order to achieve optimal performance [20]. Nanosized semiconductors have been widely used as a DSSC photoanode owing to their high absorption capability for dye sensitizers and the ability to effectively excite electrons [21][22][23].…”

Enhancing the Performance of Dye‐Sensitized Solar Cells with a Gold‐Nanoflowers Box

“…An effective way to enhancet he light-harvesting efficiency is to build al ight-scattering top layer on the TiO 2 film in DSSCs. Scattering materials, such as hollow nanostructures, [7][8][9] nanospindles, [10] nanotubes, [11] and hierarchical structures, [12][13][14][15][16] have been used to increase the absorption path-length of photons and create ac onfinementp roperty for the enhancement of light harvesting. Metal nanoparticles (NPs) are also used to enhance the light-harvesting efficiency of DSSCs through the surface plasmon resonance effect for small metal NPs [17][18][19][20][21][22][23][24] or the light-scattering effect for large metal NPs.…”