Effects of air exposure and vacuum storage on Li0.4WO3 studied by photoelectron spectroscopy

- Li donates electron in conduction band; final state satellites in W 4f level appear.
- Aging in air forms an OH/CO3 shell leading to loss of charge carriers and conductivity.
- Vacuum storage generates oxygen vacancies which can be repaired by O2.
- Li exsolution may be the origin of charge carrier loss and OH/CO3 shell formation.