2,2′-Bipyridine – A new electrolyte additive in dye-sensitized solar cells

• Published in: Solid state ionics Vol. 314; pp. 98 - 102
• Main Authors: Nguyen, Phuong Tuyet, Phan, Thu Anh Pham, Ngo, Nhung Hong Thi, Huynh, Tuan Van, Lund, Torben
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-01-2018; Elsevier BV
• Subjects: 2,2′-bipyridine; Additives; Dye-sensitized solar cell; Dye-sensitized solar cells; Dyeing; Dyes; Electrolytes; Electrolytic cells; High temperature; Ionic liquids; N-additive; N719; Nanoparticles; Nitrogen; Photovoltaic cells; Ruthenium; Studies; Thermal degradation; Thermal stability; Titanium oxides; N-additive; Dye-sensitized solar cell; 2,2′-bipyridine; N719; Thermal stability
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2017.11.023

In this work 2,2′-bipyridine (bipy) is introduced as a new nitrogen containing electrolyte additive in Dye-sensitized solar cells (DSCs) as an alternative to the commonly used 4-tert-butylpyridine (TBP). Bipy was shown to substitute the thiocyanate ligands in the N719 ruthenium dye ~4 times slower than TBP at elevated temperatures 80–85°C and therefore reduce the thermal degradation of N719 relative to TBP. The thermal stability experiments were performed in sealed glass ampules filled with a colloidal solution of N719 dyed TiO2 nano-particles in an ionic liquid electrolyte with either TBP or bipy as N-additive. The glass ampules were opened after various time intervals between 0 and 2000h of heating at either 80 or 85°C and the N719 and its degradation products were extracted from the TiO2 nano particles and analyzed by LC-UV/Vis-MS. After 1000h at 85°C in dark, 85% of N719 was intact in an electrolyte containing 0.2M bipy whereas the same number was 67% for TBP. DSCs prepared with bipy in the electrolyte was shown to perform equally well as DSCs with TBP containing electrolytes with light to electricity performance of 4.5% for both N-additives. 2,2′-bipyridine may therefore be used as an alternative to TBP as N-additive in DSCs.
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•2,2′-bipyridine (bipy) used a new N-additive in Dye-sensitized solar cells.•Degrade N719 four times slower than 4-tert-butylpyridine (TBP) at elevated temperatures (80–85 ̊C)•Improve the N719 dye stability at elevated temperatures•Same DSC performance as with TBP as with bipy