Effects of boron doping in TiO2 nanotubes and the performance of dye-sensitized solar cells

Abstract Titanium nanotubes doped with boron used as the photoelectrode for dye-sensitized solar cells were investigated. The materials were characterized by SEM, XRD, and UV–vis spectroscopy and their photoconversion efficiencies were evaluated. The chemical compositions of TiO 2 nanotubes (TNA) and boron doped TNA (B-TNA) were identified by the energy dispersive X-ray spectroscopy (EDS). XRD evidenced the presence of anatase as the main phase and presented the existence of boron elements at interstitial sites between the TiO 2 lattices. The UV–vis spectra indicated the narrowing of band gap upon doping boron into titanium nanotubes. The photovoltaic properties were measured by a current–voltage meter under AM1.5 simulated light radiation. The boron-doped TiO 2 nanotube arrays showed an enhanced performance with a photocurrent density of 7.85 ± 0.20 mA/cm 2 and an overall conversion efficiency ( η ) of 3.44 ± 0.10%. The enhanced performance was attributed to the enhanced electron injection rate and retardation of the charge recombination, which could be due to perfect matching between the LUMO of dye molecules and the conduction band of TiO 2 . Electrochemical impedance spectroscopy (EIS) measurement indicated the longer electron lifetime and reduced TiO 2 /dye/electrolyte interface resistance for boron doped TiO 2 nanotubes than that of undoped TiO 2 nanotubes.