Boron-doped carbon nanotubes as metal-free electrocatalyst for dye-sensitized solar cells: Heteroatom doping level effect on tri-iodide reduction reaction

• Published in: Journal of power sources 2018-01, Vol.375, p.29-36
• Main Authors: Yeh, Min-Hsin, Leu, Yow-An, Chiang, Wei-Hung, Li, Yan-Sheng, Chen, Guan-Lin, Li, Ta-Jen, Chang, Ling-Yu, Lin, Lu-Yin, Lin, Jiang-Jen, Ho, Kuo-Chuan
• Format: Article
• Language: English
• Subjects: Boron–doped; Carbon nanotube; Counter electrode; Dye-sensitized solar cells; Heteroatom–doped effect; Triiodide ions
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2017.11.041

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 sp2 carbon structure and thus activate the abundant free‐flowing π 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 (η) 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, η = 5.98 ± 0.20%) and is comparable to that of the cell with a Pt CE (η = 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. [Display omitted] •B-doped carbon nanotube (BCNT) was used in dye-sensitized solar cells.•BCNTs with various doping levels of boron were studied for the I3−/I− reaction.•BCNTs was synthesized by an atmospheric pressure chemical vapor deposition (CVD).•Electrocatalytic ability of CNT can be increased significantly by doping B atom.•B atoms act as the active sites by transferring charges to neighbor C atoms.