Fabrication of ZnFe2O4/TiO2 nanotube array composite to harness the augmented photocurrent density under visible light

• Published in: Applied physics. A, Materials science & processing Vol. 124; no. 1; pp. 1 - 6
• Main Authors: Boda, Muzaffar Ahmad, Shah, Mohammad Ashraf
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2018; Springer Nature B.V
• Subjects: Applied physics; Characterization and Evaluation of Materials; Charge transfer; Condensed Matter Physics; Density; Electrodes; Machines; Manufacturing; Materials science; Nanotechnology; Nanotubes; Optical and Electronic Materials; Photoelectric effect; Photoelectric emission; Physics; Physics and Astronomy; Processes; Surfaces and Interfaces; Thin Films; Titanium dioxide; Titanium oxides; Zinc ferrites
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-017-1485-1

ZnFe
2
O
4
micro crystals were deposited over electrochemically anodized TiO
2
nanotube array using cathodic electrode deposition method. TiO
2
nanotubes owing to their morphological advantage significantly harness the UV region of solar spectrum. However, the optical response of TiO
2
nanotube array in visible region is quite negligible due to large band gap. Bare TiO
2
nanotubes show a photocurrent density of 0.18 mAcm
−2
on exposing TiO
2
nanotube electrode to visible light source. However, on mounting ZnFe
2
O
4
over TiO
2
nanotubes, the photocurrent density reaches to 0.52 mAcm
−2
, which is ~ 3 times the photocurrent density shown by bare TiO
2
nanotubes under similar conditions. The appreciable enhancement in photocurrent density is attributed to effective visible light active band gap in the resulting hybrid electrode. Moreover, the suitable band edge positions in individual semiconductors facilitate the smooth charge transfer in the resulting hybrid structure on account of band bending at their interface thereby reduces the recombination rate and charge transfer resistance considerably.