Enhance the performance of dye-sensitized solar cells by balancing the light harvesting and electron collecting efficiencies of scattering layer based photoanodes

Thin titanium dioxide (TiO2) semiconductor layer with different scattering layers are investigated in dye-sensitized solar cells (DSSCs). Usually, the scattering layer is placed after the photoanode films in order to harvest more incidents light. The scattering layer based on rutile phase TiO2 is prepared, and placed in the different position of the photoanode films (on the surface of the FTO glass, between the two layers of transparent TiO2 film and after the transparent TiO2 film). We use STT, TST and TTS as marks (T and S represent the transparent TiO2 layer and the scattering layer respectively). The result of this study indicates that STT which has the lowest incident light harvesting efficiency demonstrates the highest electron collection efficiency, while TTS which has the highest incident light harvesting efficiency sacrifices the electron collection efficiency greatly. It is discovered that TST, of which the incident light harvesting efficiency basically remains unchanged compared to TTS, reveals higher electron collection efficiency and achieves the maximum photovoltaic conversion efficiency (7.0%). By applying UV-Visible and diffuse reflectance spectroscopy, electrochemical impedance spectroscopy (EIS), the effects of the incident light harvesting and electron collection efficiencies on different cells are analyzed. It makes the best use of this scattering layer and has a reference for the application of other scattering layer types.