Effect of charge compensation on the photoelectrochemical properties of Ho-doped SrTiO3 films

Effect of charge compensation on the photoelectrochemical properties of Ho-doped SrTiO3 films

Effect of charge compensation on the photoelectrochemical properties of Ho-doped SrTiO3 films
L. Zhao, L. Fang, W. Dong, F. Zheng, M. Shen, T. Wu
Applied Physics Letters, Volume 102, Issue 12, Article number 121905, (2013)
L. Zhao, L. Fang, W. Dong, F. Zheng, M. Shen, T. Wu
Charge compensation, Charge compensation mechanism, Compensation mechanism, Conduction electrons, Electrochemical impedance, Photocurrent density, Photoelectrochemical properties, Space charge regions
2013


When Ho3 ions are substituted at Sr2 sites in SrTiO3 (STO), the excess positive charges are compensated via three complementary routes: (1) strontium vacancies, (2) titanium vacancies, and (3) conduction electrons. In this study, we show that the photoelectrochemical properties of Ho-doped STO films are dependent on the charge compensation mechanisms. The compensation mechanism via the titanium vacancies exhibits the highest photocurrent density, which is 1.7 times higher than that of the pure STO sample. Based on the measured dielectric properties and electrochemical impedance spectroscopy data, we propose that the enhanced dielectric constant of the films can enlarge the width of the space charge region at the film/liquid interface, which eventually leads to the increase of the photocurrent density. Further enhancement of photocurrent density is obtained in the samples decorated with appropriate amounts of Pt nanoparticles, showing the advantage of composites for achieving the efficient photoelectrochemical property.




10.1063/1.4798829

00036951