Journal of Power Sources, Vol.375, 29-36, 2018
Boron-doped carbon nanotubes as metal-free electrocatalyst for dye-sensitized solar cells: Heteroatom doping level effect on tri-iodide reduction reaction
Heteroatom-doped carbons have been substantially applied on electrochemical applications for their exceptional electrocatalytic ability and electric conductivity. Among the doping elements, electron-deficient boron (B) is considered to be a promising heteroatom for the chemical doping of carbon materials to modify the chemically inert sp(2) carbon structure and thus activate the abundant free-flowing pi electrons. In this study, B-doped carbon nanotubes (BCNTs) with various boron doping atomic percentages (0.40-3.92 at%) are synthesized and used as a electrocatalyst on the counter electrode (CE) of dye-sensitized solar cells (DSSCs) for investigating the effect of boron doping on carbon materials. A solar-to-electricity conversion efficiency (eta) of 7.17 +/- 0.11% is achieved for a DSSC with a CE containing BCNTs with optimized B doping concentration (BCNT-0.40 at%), which is higher than that of the cells with CEs consisting of pristine carbon nanotubes (CNT, eta = 5.98 +/- 0.20%) and is comparable to that of the cell with a Pt CE eta = 7.98 +/- 0.05%). It is also noteworthy from a practical viewpoint that the developed atmospheric-pressure synthesis method for synthesizing BCNT is amenable to industrial-scale production since a requirement for vacuum system can be avoided.