Large polarization-dependent photovoltages in ceramic BaTiO3 + 5 wt.% CaTiO3

Photochemistry on a polarisable semi-conductor: what do we understand today?

“…The source of the APV comes from an interaction of phase transition, internal dipole and interaction with the incoming radiation. [103] and found to be fractional relative to the *3.15 eV band gap [104]. Similarly less than band gap photovoltages were also observed in unpoled ceramic barium titanate [105].…”

Influence of Dipolar Fields on the Photochemical Reactivity of Thin Titania Films on BaTiO3 Substrates

“…Photochemical reaction products were formed on the TiO 2 surface in patterns that correspond to the underlying domain structure of BaTiO 3 . As the film thickness increases from 10 to 100 nm, the titania more effectively screens the ferroelectric field, and the pattern of reaction products is obscured.…”

“…When illuminated, ferroelectrics such as BaTiO 3 exhibit an open-circuit photovoltage that can drive charge carriers to opposite surfaces. [3][4][5][6] Previous studies of the photochemical activity of BaTiO 3 have shown that the ferroelectric field acts to drive electrons and holes to different locations on the surface, thus creating spatially separate sites for reduction and oxidation reactions. 7,8 Reduction reactions occurred on the surfaces of ferroelectric domains in which the electric dipole was aligned with its positive end on the surface and oxidation reactions occurred on domains with the opposite orientation.…”

“…The photochemical properties of TiO 2 films supported on BaTiO 3 were investigated to test the hypothesis that dipolar fields from a ferroelectric substrate would affect the reactivity of the supported film. Photochemical reaction products were formed on the TiO 2 surface in patterns that correspond to the underlying domain structure of BaTiO 3 .…”

Photocurrent Characteristics for Mn-doped Barium Titanate Ferroelectric Single Crystals

“…Historically speaking, bulk photovoltaic effects which arises from the non-centrosymmetric nature of ferroelectric crystals were first discovered in barium titanate, [25][26][27][28] and were subsequently studied in various ferroelectric materials such as lithium niobate (LiNbO 3 ) [29,30], lead zirconate titanate [Pb(Zr,Ti)O 3 ] [31,32], bismuth ferrate (BiFeO 3 ) [33,34] and so forth. These studies were conducted with the aim mainly of the applications for non-linear optics using photorefractive effects and two-wave mixing.…”