Pristine Anatase Research Articles

Photoluminescence study on defects in pristine anatase and anatase-based composites

Under 325nm laser light irradiation at room temperature in oxygen gas, the photoluminescence (PL) intensity of pristine anatase TiO2 decreases considerably and then it recovers reversibly with the same laser light irradiation at room temperature in vacuum. This result gives important information on the oxygen defects at anatase particle surfaces and may also clarify the origin of largely Stokes shifted broad PL band in pristine anatase. New reversible photoinduced spectral change has been also found in anatase–AgI composites for replacing atmosphere (vacuum↔oxygen gas) under 325nm laser light irradiation at room temperature. This spectral change may arise from the excitation energy transfer between excitons in AgI domain and photoinduced oxygen defects at the anatase particle surfaces.

Lithium ion insertion in nanoporous anatase TiO2 studied with RIXS

Lithium insertion into nanoporous anatase TiO2 electrodes has been studied using resonant inelastic soft-x-ray scattering spectroscopy (RIXS). We have measured Ti 2p absorption, L2,3-emission and resonant inelastic scattering spectra of pristine anatase TiO2 and Li inserted TiO2. Inelastic scattering features in RIXS spectra of pristine TiO2 are assigned to charge-transfer excitations. Low energy-loss features for Li inserted TiO2 electrodes, appearing within t2g bands, due to d–d excitations, indicate the presence of Ti3+ states. The experimental observations suggest strong electron correlation in anatase TiO2 introduced by the Li-insertion.