The Use of Rutile‐ and Anatase‐Titania Layers towards Back Light Scattering in Dye‐Sensitized Solar Cells

Abstract

Dye‐sensitized solar cells (DSCs) with nanocrystalline TiO2 (NCT) particles (ca. 20 nm) as foundation layer and mesoporous anatase phase microspheres (AMT) or rutile phase microspheres (RMT), as the back light‐scattering layer, were fabricated. The phase‐pure AMT, 0.42 μm or RMT particles, 0.50 μm were obtained at 500 oC and 900 oC, respectively. The DSCs employing NCT/AMT and NCT/RMT bi‐layered films depicted power conversion efficiencies of 5.9% and 6.3%, respectively, compared to 4.0% of DSCs with only NCT films. The efficiencies were improved up to 9.0% after depositing compact nano‐TiO2 layers beneath the NCT film. The optical and electrochemical investigations of the DSCs quantitatively elucidated, through longer electron life time and enhanced back light scattering, the substantial improvement in power conversion efficiency to the texture tuning of titania films, in particular by the rutile phase.

Supramolecular Approach in Energy Conversion Devices

“…[170][171][172][173][174][175] These activities included the preparation of colloidal TiO 2 using distinct methods and different deposition techniques, such as spin-coating, painting and screenprinting. 176,177 Homogeneous semiconductor films with controlled transparency had been obtained with the proper colloidal TiO 2 for automated process. Conducting plastic materials were also tested as the electrode substrate in association with a polymeric gel as an electrolyte medium resulting in wholly flexible solar cells.…”

“…[218][219][220][221] The development of a screen-printable paste with improved morphological and optical characteristics for the automated deposition of submicrometer TiO 2 resulted in 32% enhanced conversion efficiency. 176,177 Another successful approach is the photoanode engineering to minimize recombination effects by treating the TiO 2 or FTO surface with a thin cover layer of compact semiconductor oxide 222 or even insulating oxide 223 that efficiently blocks charge recombination decreasing power conversion efficiencies. 224 The recombination at FTO/electrolyte interface occurs through the direct physical contact between the FTO and the mediator that percolates through the mesoporous TiO 2 semiconductor film.…”

Investigation of Rutile and Anatase Mesoporous SiO2@TiO2 Particles in the Scattering Layer of Dye‐Sensitized Solar Cells

“…In addition, rutile TiO 2 has a high reflectivity but a low surface area. Therefore, it can reflect incident light effectively, but the absorption rate of the sensitizing dye is reduced [5]. To improve this issue, the surface of the particles was made mesoporous.…”

New LbL‐TiO2/ZnO Compact Films to Improve Performance of Dye‐Sensitized Solar Cells

“…Investigations on DSCs have mainly focused on their components, such as use of different dyes and mesoporous semiconductor oxide, deposition techniques, new electrolytes and design of photoanode . Another aspect is the understanding of processes that limit the conversion efficiency and their control . In particular, undesired charge recombination at the FTO/electrolyte interface can be prevented by the insertion of compact layers on the FTO surface, beneath the meso‐TiO 2 film ,…”