Photocurrent enhancement for Ti-doped Fe₂O₃ thin film photoanodes by an in situ solid-state reaction method.
In this work, a higher concentration of Ti ions are incorporated into hydrothermally grown Ti-doped (2.2% by atomic ratio) micro-nanostructured hematite films by an in situ solid-state reaction method. The doping concentration is improved from 2.2% to 19.7% after the in situ solid-state reaction. X-ray absorption analysis indicates the substitution of Fe ions by Ti ions, without the generation of Fe²⁺ defects. Photoelectrochemical impedance spectroscopy reveals the dramatic improvement of the electrical conductivity of the hematite film after the in situ solid-state reaction. As a consequence, the photocurrent density increases 8-fold (from 0.15 mA/cm² to 1.2 mA/cm²), and it further increases up to ∼1.5 mA/cm² with the adsorption of Co ions. Our findings demonstrate that the in situ solid-state reaction is an effective method to increase the doping level of Ti ions in hematite films with the retention of the micro-nanostructure of the films and enhance the photocurrent.
Anhui Key Laboratory of Nanomaterials and Technology and Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China.
Chunhui
C
Miao
Tongfei
T
Shi
Guoping
G
Xu
Shulin
S
Ji
Changhui
C
Ye