Electrical and photocatalytic properties of boron-doped ZnO nanostructure grown on PET-ITO flexible substrates by hydrothermal method

Abstract

Boron-doped zinc oxide sheet-spheres were synthesized on PET-ITO flexible substrates using a hydrothermal method at 90 °C for 5 h. The results of X-ray diffraction and X-ray photoelectron spectroscopy indicated that the B atoms were successfully doped into the ZnO lattice, the incorporation of B led to an increase in the lattice constant of ZnO and a change in its internal stress. The growth mechanism of pure ZnO nanorods and B-doped ZnO sheet-spheres was specifically investigated. The as-prepared BZO/PET-ITO heterojunction possessed obvious rectification properties and its positive turn-on voltage was 0.4 V. The carrier transport mechanisms involved three models such as hot carrier tunneling theory, tunneling recombination, and series-resistance effect were explored. The BZO/PET-ITO nanostructures were more effective than pure ZnO to degrade the RY 15, and the degradation rate reached 41.45%. The decomposition process with BZO nanostructure followed first-order reaction kinetics. The photocurrent and electrochemical impedance spectroscopy revealed that the B-doping could promote the separation of photo-generated electron-hole pairs, which was beneficial to enhance the photocatalytic activity. The photocurrent density of B-doped and pure ZnO/PET-ITO were 0.055 mA/cm2 and 0.016 mA/cm2, respectively. The photocatalytic mechanism of the sample was analyzed by the energy band theory.