An innovative TiO2 nanoparticle/nanofibre/nanoparticle, three layer composite photoanode for efficiency enhancement in dye-sensitized solar cells

• An innovative type of composite photoanode consisting of a TiO2 nanofibre (NF) layer sandwiched between two TiO2 nanoparticle (NP) layers has been fabricated and tested in dye sensitized solar cells.
• DSSCs fabricated with the TiO2 NP/NF/NP composite three layer photoanode sensitized with N 719 dye showed the highest efficiency of 7.09% where as the DSSC with TiO2 nano particle photoanode with same thickness and the same electrolyte showed an efficiency of 5.38%.
• The increased efficiency has been attributed to enhanced light harvesting due to scattering within the TiO2 nanofibre structure.
• The composite photoanode with an electrolyte with two iodide slats increased the DSSC efficiency to 8.80% representing an impressive overall efficiency enhancement by 64% compared to a corresponding DSSC made with conventional TiO2 nanoparticle (NP) photoanode and an electrolyte with the single iodide salt Pr4NI.

An innovative type of composite photoanode consisting of a TiO2 nanofibre (NF) layer sandwiched between two TiO2 nanoparticle (NP) layers has been fabricated and tested in dye sensitized solar cells. After sintering, the nanofibres in the layer have turned to an elongated bead type nanostructure. DSSCs fabricated with the TiO2 NP/NF/NP composite three layer photoanode sensitized with N 719 Ruthenium dye and a electrolyte solution consisting of tetrapropylammonium iodide and iodine dissolved in acetontrile and ethylene carbonate co-solvent showed the highest efficiency of 7.09% where as the DSSC with TiO2 nano particle photoanode and the same electrolyte showed an efficiency of 5.38%. The increased efficiency has been attributed to enhanced light harvesting due to scattering within the TiO2 nanofibre structure. The efficiency of the highest efficiency DSSC has been further enhanced by using the “mixed cation effect” where the single iodide salt, Pr4NI, in the electrolyte has been replaced by two iodide salts KI and Pr4NI resulting an efficiency of 8.80%. The combined use of the TiO2 three layer composite photoanode and the mixed cation iodide salt containing electrolyte represents an impressive efficiency enhancement by 64% compared to a corresponding DSSC made with TiO2 nanoparticle (NP) photoanode and an electrolyte with the single iodide salt Pr4NI.

TiO2 nanoparticle/nanofibre/nanoparticle, three layer composite photoanode.Figure optionsDownload as PowerPoint slide